US Republican presidential front-runner Donald Trump has come under fire from his rivals for saying Muslims hate the United States at a debate that was relatively free of the gut-punching attacks that have dominated past encounters.
Trump, the front-runner who could tighten his grip on the Republican presidential nomination battle if he wins Florida and Ohio on Tuesday, defended his belief, as stated in television interviews, that followers of Islam "hate us".
"We have a serious problem of hate. There is tremendous hate," Trump said.
But Trump's rivals, Senator Marco Rubio of Florida, Senator Ted Cruz of Texas and Ohio Governor John Kasich said the United States needs to maintain good relations with Muslim countries in the Middle East to help in the fight against Islamic State militants.
"We are going to have to work with people in the Muslim faith even as Islam faces a serious crisis within it," Rubio said.
Kasich, looking to win his home state of Ohio on Tuesday in order to keep his candidacy going, said Middle Eastern allies in the Arab world are essential.
"The fact is if we're going to defeat ISIS, we're going to have to have those countries," he said, citing Saudi Arabia, Jordan and Egypt.
Trump said he would consider as many as 40,000 US troops on the ground in the region to help defeat Islamic State, saying he would complete the mission quickly and bring them home to focus on rebuilding the United States.
The CNN-hosted debate took place at a crucial time, days before primary votes in Florida and Ohio that could catapult Trump even further despite an intense anti-Trump movement by establishment Republicans who are trying to deny him the party's presidential nomination.
Both the Florida and Ohio Republican primaries award delegates on a winner-take-all basis, meaning that the winner of the popular vote is awarded the state's entire slate of delegates, making a victory in either state a big prize.
The two-hour debate included a sober discussion of pressing challenges from illegal immigration to reform of Social Security to free trade deals, a marked departure from the finger-pointing schoolyard taunts that the candidates have engaged in past debates.
Trump got a fresh injection of campaign momentum on Thursday with plans by rival Ben Carson, who is popular with conservatives, to endorse him.
Trump said Carson, a retired neurosurgeon who dropped out of the race March 4 after failing to gain traction in early voting states, would endorse him on Friday at an event in Florida.
The endorsement could help Trump settle the nerves of those conservative voters who have doubts about whether he truly is one of them.