Republican presidential front-runner Donald Trump — apparently sensing trouble and feeling the heat of the Republican backlash against his campaign ahead of the key March 15 winner-take-all Florida primary — asked the crowd in Orlando on Saturday to take a pledge that they will vote for him "even if there are hurricanes or whatever."

"Let's do a pledge. Who likes me in this room?" Trump asked the crowd, CNN reported. "I've never done this before. Can I have a pledge? A swearing? Raise your right hand."

Trump then asked the audience to repeat after him: "I do solemnly swear that I, no matter how I feel, no matter what the conditions, if there are hurricanes or whatever, will vote on or before the 12th for Donald J. Trump for President."

As the crowd cheered, Trump reminded them: "Now I know. Don't forget you all raised your hands. You swore. Bad things happen if you don't live up to what you just did."

The rowdy rally at a University of Central Florida arena in Orlando, Florida, featured frequent interruptions by protesters who heckled Trump as he delivered an hour-long speech. The protests became so frequent and intense that at one point Trump asked them to stop so he could continue his speech. "Can the protesters stop for a couple of seconds so we can talk?" Trump asked.

Meanwhile, before the rally, Trump issued a statement modifying his stance a second time on the use of torture to extract information from terror suspects. Just a day after promising that he would not order military officials to violate U.S. or international laws, Trump said he would still not rule out torture on terror suspects but "we're going to stay within the laws."

"We're going to have those laws broadened because we're playing with two sets of rules: their rules and our rules," Trump said, referring to the tactics of torture and brutal executions employed by the Islamic State (ISIS) jihadist and terrorist organisation.

On Friday, Trump vowed in a statement that he would "not order our military or other officials to violate those laws."

He was referring to an earlier statement he made where he defended the use of waterboarding and even "a lot further than waterboarding" to extract information from terror suspects that could help in prosecuting the campaign against terror.

Those remarks drew scathing criticism from former national security officials, including former CIA Director Michael Hayden, who warned Trump that U.S. military officials would not follow any illegal orders from the President.

But on Saturday, Trump once again sounded hawkish, telling his supporters, "We have to obey the laws, but do you think ISIS is obeying the laws?"