Republican presidential candidates Ted Cruz and Marco Rubio unleashed a barrage of attacks on front-runner Donald Trump in the last debate before a pivotal series of primaries.
The senators sought to blunt Mr Trump’s momentum after he has won three out the first four contests.
Immigration, healthcare and outreach to Latino voters dominated the debate.
But like previous forums, the debate quickly devolved into long periods of shouting and personal insults.
Mr Rubio rolled out a new line of attacks, saying Mr Trump in his businesses hired foreign workers rather than Americans.
Mr Trump shot back: “I hired tens of thousands of people. You’ve hired nobody.”
The billionaire real estate mogul found himself increasingly on the defensive about his business dealings, his conservative credentials and his support for Israel.
The stakes have been raised for the candidates. Next Tuesday, known as Super Tuesday, millions of voters in 11 states will cast ballots in the Republican race.
A quarter of the total numbers of delegates needed to the secure the nomination will be up for grabs that day.
- Mr Cruz said Mr Trump’s reputation as a dealmaker means he can not be trusted to appoint conservative justices to Supreme Court
- Most of the candidates were asked about releasing their tax returns; Mr Cruz and Mr Rubio pledged to release them in days while Mr Trump demurred
- Moderator Maria Celeste grilled Mr Trump on how he will appeal to Latino voters in the general election
- Mr Trump addressed criticisms from Mexico’s former president who said the country would never pay for a border wall between the two counties. “Mexico will pay for the wall,” Mr Trump said. “The wall just got 10 feet taller”
- Ohio Governor John Kasich touted his successes in his state including overcoming a budget deficit and bringing new industries to the state
- Former neurosurgeon Ben Carson struggling to participate at one point called out: “Can someone attack me?”
Mr Trump has been extremely popular despite his controversial comments about deporting millions of undocumented workers and banning Muslims from travelling to the United States.
After four primary and caucus competitions, Mr Trump has 82 Republican party delegates, Senator Ted Cruz has 17 and Marco Rubio has 16. To become the Republican party’s nominee, a candidate has to have 1,237 total state delegates.
Mr Carson has said he will not be quitting the race anytime soon, despite a poor showing in polls and in state contests so far.
Mr Kasich, billing himself as a moderate, compassionate alternative to his more conservative colleagues, has been pressured to drop out by some Republicans so a non-Donald Trump frontrunner can emerge.
Mr Cruz placed third in three consecutive state races and Mr Rubio had a major stumble in a debate before the New Hampshire primary. He repeated himself several times and was ridiculed online.
Mr Trump has said he is confident heading into Super Tuesday.
“It’s going to be an amazing two months,” he said after winning the Nevada contest on Tuesday. “We might not even need the two months, folks, to be honest.”
He has gone after Mr Cruz recently, calling him a “liar” and questioning his campaign strategies.
Mr Rubio, meanwhile, is seeking the backing of establishment Republicans and has said the bid for the nomination is now a “three-person race”.