Donald Trump has won primaries and caucuses in 14 states and has 460 delegates. (AFP Photo)
Ahead of tomorrow's crucial primaries, all eyes are on Florida and Ohio where Republican presidential hopefuls Marco Rubio and John Kasich respectively are engaged in a do-or-die battle with party's frontrunner Donald Trump, whose campaign lately has been marred by unrest.
To stay in the race to the White House both Mr Rubio, 44, and Mr Kasich, 63, need to win the primaries in their respective states, which would likely propel Mr Trump closer to bagging the party's presidential nomination for the November 8 elections.
The events tomorrow has been dubbed "Super Tuesday 2.0", when five states will go to the polls including Florida, Illinois, Missouri, North Carolina and Ohio as well as the Northern Mariana Islands.
More than 360 delegates are stake in the primaries in these five states, electioneering before which has seen an unprecedented level of violence and protests at public rallies of Trump, who had to cancel his Chicago meeting as groups of supporters and protesters clashed on Friday night.
In Ohio, its popular governor John Kasich is in a tight race with Mr Trump, latest opinion polls said yesterday.
To give a boost to his campaign, the former Republican presidential nominee Mitt Romney has announced that he would campaign in favour of Mr Kasich in Ohio.
The strategy for Mr Romney, who has openly called for defeat of Mr Trump, is to prevent the outspoken New Yorker from winning the majority of the delegates so that the final decision on the nomination is taken at the Cleveland convention in July.
In a fast-changing political equation, Mr Trump, 69, last night announced to cancel his rally in Florida and instead campaign in Ohio, which his managers said would be attended by thousands of people.
In order to seal the deal, Mr Trump desperately needs to win both Florida and Ohio -- which are winner-takes-all states.
Mr Trump has won primaries and caucuses in 14 states and has 460 delegates, but he is just 100 delegates ahead of nearest rival Senator Ted Cruz who has won seven states and has 360 delegates.
Mr Rubio with three wins has 163 delegates, while Mr Kasich who is yet to win a single state has 63 delegates. To win the party's presidential nominee, the candidates need to have the support of 1,237 delegates out of a total of 2,472 delegates.
Joining Mr Romney's strategy, Mr Rubio has also asked his supporters to vote for Mr Kasich in Ohio.
Mr Rubio has also called Mr Trump's language "dangerous."
"If we reach a point in this country where we can't have a debate about politics without it getting to levels of violence and anger," he told CNN, "we're going to lose our republic."
However, in his own home state of Florida Rubio is fighting the toughest political battle of his life.
Despite having pitched his tent in the state for the past one week, Mr Rubio is trailing behind Mr Trump with a double digit margin.
With stakes high in Ohio, Mr Trump launched his characteristic personal attack on Mr Kasich alleging that he has been absent from the state for long.
Late in the night, Mr Kasich accused Mr Trump of running a campaign of lie against him.
"Trump is lying to Ohioans, and we are consulting with our lawyers on our next steps. We are 100 per cent certain that John Kasich will be on the ballot in Pennsylvania," said Rob Nichols, spokesman for John Kasich.
"Trump's dishonest tweets and robocalls means his team either knows nothing about Pennsylvania election law or he's just scared to death we're going to beat him. Donald Trump continues to play gutter politics, America deserves better and he owes Ohioans an apology for lying to them," Mr Nichols said.
Tomorrow's election would be the first test for Mr Trump after a series of protests at his rallies.