Donald Trump outlined more controversial steps he would take in the name of national security if he becomes president, calling Sunday for the return of the widely discredited interrogation technique of waterboarding and repeating that he’d track Muslims and shutter mosques in the U.S.

Insisting that the United States “would have to be strong,” Trump said that waterboarding Islamic State extremists would be “peanuts” compared with the group’s beheadings of American and British hostages.

“I would bring it back. I think waterboarding is peanuts compared to what they’d do to us … what they did to James Foley when they chopped off his head,” Trump said on ABC's "This Week" referring to the American journalist beheaded by Islamic State in August 2014. “That’s a whole different level and I would absolutely bring back interrogation -- and strong interrogation.”

In the wake of the Sept. 11, 2001, attacks, the Bush administration turned to waterboarding, a method in which a suspect is made to feel like he’s drowning, to try to extract information from Al Qaeda suspects. The effort proved mostly futile in producing useful intelligence about planned attacks and led to false confessions, according to the executive summary of a long-delayed Senate report that came out late last year. President Obama formally ended the program when he took office in 2009.

Trump, though, said he sees waterboarding as a useful counterbalance to the violent murders committed by Islamic State.

“You know, they don’t use waterboarding over there; they use chopping off people’s heads,” he said.

Trump also doubled down on his calls for a database to monitor Muslims and the possibility of shuttering mosques.

At a rally in Birmingham, Ala., on Saturday, Trump again brought Muslims to the forefront – a topic he’s focused on in the aftermath of the Paris terror attacks. Trump told the estimated 10,000 people in attendance he saw images of Arab Muslims cheering in New Jersey after the Sept. 11 attacks.

“There were people that were cheering on the other side of New Jersey where you have large Arab populations,” he said on “This Week.” "They were cheering as the World Trade Center came down. I know it might be not politically correct for you to talk about it, but there were people cheering as that building came down -- as those buildings came down, and that tells you something. It was well covered at the time.”

Rumors have surfaced over the years about Muslims cheering in Paterson, N.J., as the twin towers collapsed, but those claims were discounted by local police at the time.

During the rally, a protester from the Black Lives Matter movement heckled the real-estate mogul. When asked about it in a separate interview Sunday on “Fox & Friends,” Trump suggested the protester should have been “roughed up.”

“Maybe he should have been roughed up because it was absolutely disgusting what he was doing," Trump said. “The man that was — I don't know, you say 'roughed up' — he was so obnoxious and so loud. He was screaming. I had 10,000 people in the room yesterday — 10,000 people. And this guy started screaming by himself.”

Since he entered the GOP presidential race over the summer, Trump has catapulted to the top of the crowded field, tapping into an electorate discontented with the political establishment. And with less than three months until ballots are cast, he remains toward the top of polls in the early voting states of Iowa, New Hampshire and South Carolina.

Trump also stoked fears among the Republican Party that if he does not capture the party's nomination, he will seek a third-party run for president. Though he signed a pledge months ago promising to support the Republican nominee in what was seen as something of a peace agreement between Trump and party leadership, he said Sunday that he’s still considering running as an independent.

“I will see what happens. I have to be treated fairly. You know, when I did this, I said I have to be treated fairly. If I'm treated fairly, I'm fine,” he said Sunday on “This Week.”