Donald Trump said Tuesday he would have to "strongly consider" closing some U.S. mosques with radical leadership if he were elected president.

In interviews with MSNBC and CNBC, he said he surveillance should be stepped up — including in mosques.

"Surveillance took a big turn over the last 48 hours," Trump told CNBC, referring to Friday's attacks in Paris. "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.'"

He said "you're going to have to watch and study the mosques because a lot of talk is going on at the mosques."

"And from what I heard, in the old days — meaning, a while ago — we had great surveillance going on in and around mosques in New York City," Trump said Monday on MSNBC's Morning Joe.

In 2012, Muslim leaders in New Jersey sued the New York City Police Department in connection with surveillance at mosques and Muslim neighborhoods by the NYPD's Demographics Unit. The surveillance program had been supported by former New York Mayor Michael Bloomberg — but last year New York Mayor Bill de Blasio disbanded the unit.

According to the Associated Press, with the CIA's help, the NYPD unit assembled databases on where Muslims lived, shopped, worked and prayed. It also infiltrated Muslim student groups, put informants in mosques and monitored sermons.

The Associated Press contributed to this story.