Republican presidential candidate Donald Trump says he would consider closing U.S. mosques with radical leadership because of the Paris attacks if he were elected president.

"I would hate to do it, but it's something that you're going to have to strongly consider," Trump told MSNBC in a phone interview Monday.

Trump and his rivals have been working to articulate how they would respond to last week's attacks, which killed 129 people and left 352 wounded.

Trump, who has been pushing for a more aggressive response, also said Americans must reassess some of their civil liberties in response to growing threats from ISIS.

"We have to be much tougher," he said in another interview on CNBC. "We are going to have to give up certain privileges that we've always had."

"Surveillance took a big turn over the last 48 hours," he added. "Forty-eight hours ago everybody was saying, 'Well, we want our freedoms, we don't want this to happen.' And now, all of sudden, people are saying, 'Hey listen, you can listen to my phone conversations.'"

That surveillance, he argued, should include intelligence-gathering in and around mosques.

"Well you're going to have to watch and study the mosques because a lot of talk is going on at the mosques," said Trump, who complained that New York City, where he lives, has ramped down its efforts to infiltrate places of Muslim worship.

Trump appeared to be referring to the New York Police Department's Demographics Unit, which The Associated Press reported in 2011 was spying on Muslims and mosques around the city with help from the CIA. The group assembled databases on where Muslims lived, shopped, worked and prayed, infiltrated Muslim student groups, put informants in mosques and monitored sermons.

The NYPD, under Mayor Bill de Blasio, announced it had abandoned the program in April of last year following lawsuits and complaints.

Trump told a weekend rally that things would have turned out differently in Paris had the victims of the attacks been armed with guns. He repeated that assertion in the CNBC phone interview.

"Had there been some guys with a gun, there would have been a shoot-out and probably the primary people that got whacked would have been the killers," he said. "Had there been other people carrying weapons, you would have had a lot different story, believe me."

Trump criticized President Barack Obama for not moving earlier to destroy the Islamic State sites that France bombed over the weekend. He said the U.S. should be going more aggressively after the group's oil and financing and pressing other countries to intensify their fighting against the radicals.