Donald Trump has won three more states, Michigan, Mississippi and Hawaii, in his bid to be the Republican White House nomination.
In the Democratic race, Bernie Sanders had a surprise victory in Michigan, but Hillary Clinton increased her overall lead with a big Mississippi win.
Ted Cruz won a Republican-only race in Idaho.
The states are the latest to choose candidates to compete in November's presidential election.
It was a terrible night for Republican Florida Senator Marco Rubio, who came in a distant fourth in both Michigan and Mississippi, a week before his must-win contest in his home state.
Election results - as they come in
Has Trump killed off Rubio?
US media: Has Sanders changed Democratic race?
Mr Trump, a businessman with no experience of elected office, leads the polls in Florida, from where he delivered his victory speech on Tuesday night.
"One of the things I am most happy about is the turnout has been just massive… I think it's the single biggest story in politics today," he said at a press conference in Jupiter.
Analysis - Nick Bryant, BBC News, Detroit, Michigan
With his victories, Donald Trump has solidified his position as the Republican front-runner, withstanding a barrage of negative advertisements questioning everything from his business acumen to his use of vulgar and profane language.
Rather than deliver a conventional victory speech, the billionaire held a news conference and conducted what looked in parts like an infomercial, arguing that products that bear his name, like bottled water and wine, are commercial successes.
But it's the Trump political brand that's not only proving highly popular but also resilient to attacks from establishment Republicans who have intensified their attacks in the hope of slowing his momentum.
Showing how the normal political rules do not apply, Trump reckoned that one of the attack ads, bleeping out various swear words he's uttered during the campaign, actually boosted him because it showed that he's not bound by political correctness and tells it like it is.
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He also said he would be more presidential than anybody except Abraham Lincoln and that "no one is more conservative than me".
The Democratic opponent Mr Trump is most likely to face if he gets the Republican nomination, former US Secretary of State Hillary Clinton, addressed voters in Ohio after her Mississippi win.
"Running for president shouldn't be about delivering insults," said Mrs Clinton, in a thinly veiled dig at the outspoken Mr Trump.
"It should be about delivering results."
Who won where
Republican
Donald Trump: Michigan, Mississippi and Hawaii
Ted Cruz: Idaho
Democratic
Hillary Clinton: Mississippi
Bernie Sanders: Michigan
Mr Sanders' win in Michigan came as a shock after weeks of polling that suggested Mrs Clinton was well ahead.
"I am grateful to the people of Michigan for defying the pundits and pollsters and giving us their support," Mr Sanders said in a statement following his win.
"This is a critically important night. We came from 30 points down in Michigan and we're seeing the same kind of come-from-behind momentum all across America."
Analysts say conservative firebrand Mr Cruz appears to be the only candidate capable of stopping Mr Trump, who has been fiercely criticised by the Republican establishment.
The party's 2012 nominee, Mitt Romney, described Mr Trump as a bully and a fraud who would lose a general election because of his extreme positions on immigration and Islamic State.
A central plank of Mr Trump's campaign is to deport 11m undocumented migrants and build a wall on the southern border, paid for by Mexico.
The primary and caucus elections determine the number of delegates assigned to each of the candidates.
The delegates then endorse their candidate at the party conventions in July. To secure their party's nomination, a candidate must win a majority of delegates.
Source: BBC WORLD NEWS
On Super Tuesday Donald Trump's hostile takeover of the Republican Party should come even closer, and like stiff-collared executives in some wood-panelled boardroom trying belatedly to fight off a corporate raid, the GOP high command seems incapable of stopping him.
For them, Super Tuesday could become Black Tuesday. Friday must have been gloomy enough, when Chris Christie, supposedly a card-carrying member of the establishment, kissed Donald Trump's hands and gave this political outsider his endorsement.
Christie's blessing came as a bolt from the blue, and taught us once more to expect the unexpected. But shouldn't the establishment - and us in the media, for that matter - have seen the billionaire coming? After all, for years the Republican standard bearers have been vulnerable to a challenge from an anti-establishment candidate.
Before going on, we should say what we mean by the Republican Party establishment, a term regularly bandied around but rarely explained. Fifty years ago, it was easier to identify.
It was an eastern establishment dominated by Wall Street bankers and corporate executives, who were strongly pro-business, ideologically moderate and politically pragmatic.
Nelson Rockefeller, the scion of the banking dynasty and Governor of New York - who lived, like Donald Trump, in great splendour on Fifth Avenue - was their figurehead.
These days, however, the Republican establishment is harder to define and more diffuse, which also explains why it is easier to topple.
Commonly it is broadly taken to mean the Republican National Committee, senior office-holders (like Chris Christie), present and past, conservative lobbyists, like the US Chamber of Commerce, big-money donors and opinion-formers, who write for publications like the Weekly Standard, the National Review and op-ed pages of the Wall Street Journal. But that definition is open to debate. Its disparate membership explains its inability to exert control.
The most obvious reason for the decline of the Republican establishment has been the rise of anti-establishment adversaries. The Tea Party, an insurgent grassroots movement that emerged after Barack Obama's inauguration, has posed the most serious threat.
Its hatred of the president is matched almost by its loathing for establishment Republicans in Washington, like the Senate Majority leader Mitch McConnell, who activists complain could have done more to thwart the White House.
Tea Party primary challengers have ousted senior establishment fixtures, like Senator Richard Lugar, who represented Indiana for 36 years.
The "Hell No" Caucus on Capitol Hill, a rump of 50 or so Tea Party-backed Republican hardliners in the House of Representatives, was strong enough to push the former House Speaker John Boehner to the point of resignation.
As for opinion formers, most of the loudest and dominant voices in the modern-day conservative movement, like the talk show hosts Rush Limbaugh and Glenn Beck and the commentator Ann Coulter, are vehement critics of the establishment.
The Fox News channel, even though it has often given a platform for anti-establishment voices, doesn't fall into that same category. But it has become a rival power centre, outside the control of the GOP high command.
Going into the 2016 campaign, there were big clues that establishment candidates would be vulnerable. Eric Cantor, the House Republican majority leader, was ousted, unexpectedly, ahead of the 2014 congressional mid-terms. Boehner was pressured to resign as House Speaker.
However, most of us made the mistake of interpreting the results of the congressional mid-term elections as a major setback for insurgents, because they failed to make more breakthroughs.
Their attempt, for example, to oust the Republican Senator Thad Cochran in Mississippi, then a six-term incumbent, was unsuccessful. In Kentucky, Mitch McConnell also crushed a Tea Party challenge in the Republican primary.
According to polls, Tea Party favourites, like Sarah Palin and Michelle Bachmann, also lost their lustre.
Even though the Tea Party was waning - in October last year, a Gallup poll suggested its support had dwindled to just 17% - the anger and rage that gave rise to it had not gone away.
Conservative insurgents just needed a better candidate and more effective mouthpiece.
The most obvious figure was Ted Cruz, a long-time darling of the Tea Party. But Donald Trump has proved more adept at giving voice to the politics of frustration and rage, even though he is not a Tea Party candidate per se.
Long before announcing his presidential bid, the billionaire had already burnished his reputation among Tea Party devotees by becoming the most prominent "birther" - claiming, falsely, that Barack Obama is not a natural-born citizen of the United States. His outspoken attacks on Mexicans and Muslims, combined with his contempt for political correctness, are music to insurgents' ears.
Another analytical failure was to assume that the Republican establishment could do in 2016 what it has done successfully in the past seven presidential elections: to see its anointed favourite become the nominee.
George Herbert Walker Bush, Bob Dole, George W Bush, John McCain and Mitt Romney. All were Republican establishment favourites. What's perhaps most remarkable about that run of success for the party's high command is that it continued so long.
We should have paid more attention to the difficulty Mitt Romney had securing the nomination in 2012 and also the extent to which he was assisted by the absence of a strong establishment rival.
A central problem for the GOP high command this year, of course, has been that Marco Rubio, John Kasich, Jeb Bush and Chris Christie have split the vote.
Not only that, we should have been more mindful of Rick Santorum's surprise showing four years ago. The right-wing former Pennsylvania Senator won 11 states and four million votes, even though he was viewed at the outset of the race as a woefully weak candidate.
It suggested that the Republican establishment would face a more serious problem in 2016 if a more compelling right-winger emerged.
Besides, one of the reasons why anti-establishment fervour is so strong this time round is because the grass roots is so fed up with being saddled with establishment moderates, like Romney.
Had we reached further back into Republican Party history we would have seen that hostile takeovers have succeeded in the past.
In 1980, Reagan ran as an anti-establishment candidate, beating the blue-blood Republican George HW Bush, a scion of the establishment.
Then there was Barry Goldwater's success in 1964, when he scored that highly symbolic victory over Nelson Rockefeller, the great pillar of the establishment.
The victory of an Arizonian right-wing firebrand over a New York moderate personified the shift in the Republican Party's centre of gravity during the civil rights era from the north-east to the south and south-west.
It changed the character of the party, setting it on its present course.
Revulsion right now of the permanent political class and party elites seems to be a global phenomenon, but in America it is particularly pronounced, on the left as well as the right.
But an anti-establishment figure like Donald Trump would not have become so strong had not the party establishment become so weak. The GOP, the Grand Old Party, has been ripe for a takeover for years.
Collected From : BBC WORLD NEWS
EU to grant Turkish citizens visa-free travel to Schengen zone latest by June in return for cooperation on refugees.
Turkey has asked for an additional $3.3bn from the European Union to help it check the flow of refugees across the Aegean Sea, according to officials.
Turkey is due to receive $3.3bn until the end of 2018 to cover the costs of dealing with the refugees, but it has reportedly asked for double the amount.
Martin Schulz, head of the European Parliament, said the request came at a summit in Brussels on Monday between Ahmet Davutoglu, Turkish prime minister, and the EU leaders.
Under a draft proposal, Turkey and the EU could cooperate to end the flow of irregular refugees to Greek islands and start resettling Syrian refugees directly from Turkey to the bloc.
In exchange for readmitting refugees from Greece to Turkey, Brussels will grant Turkish citizens the right to travel to the EU's Schengen zone without a visa latest by end of June 2016.
The Turkish government is also trying to secure the country's EU membership.
"Turkey is ready to work with the EU, and Turkey is ready to be a member of the EU as well," Davutoglu said before the summit, expressing hope that the talks "will be a success story and a turning point in our relations".
Temporary home
Turkey is a temporary home to an estimated 2.75 million refugees, many from the conflict in Syria.
It is also a transit country for waves of people heading to Europe from Pakistan, Afghanistan and Iraq.
"We are not sending them, they are going to Greece by sea and many of them are dying," Recep Tayyip Erdogan, Turkey's president, said, criticising the EU for the unwillingness to take in refugees as well as their demands on Turkey to halt the flow of people.
"We have rescued close to 100,000 from the sea. Others are puncturing their boats and causing their deaths."
On Sunday, at least 25 people drowned off the Turkish coast while trying to reach Greece.
The Greek coastguard launched a search-and-rescue mission for people believed to be missing from the accident near the Turkish town of Didim.
At least 15 people were rescued and brought to land in the care of emergency aid workers.
About 13,000 people are living in precarious conditions in Greece as they wait for authorities to let them into Macedonia so they can move towards Western Europe.
The UN High Commissioner for Refugees (UNHCR) says a humanitarian crisis is quickly unfolding at the border, with refugees living in makeshift camps and in the open, as authorities allow only 250 a day to pass through.
More than one million asylum seekers have arrived in Europe since the start of 2015 - the majority fleeing the war in Syria - with nearly 4,000 dying while crossing the Mediterranean.
Collected From : AL-JAZEERA
