Republican presidential front-runner Donald Trump on Sunday said he’s not “playing on fears,” when it comes to his assessment of how to fight ISIS, but rather he’s “playing on common sense.”

“I don’t want to play on fears. I understand the whole world,” Trump said in an interview with CBS’ “Face the Nation” that aired Sunday. “I have Muslim friends who are great people. And by the way, they tell me, ‘there’s a big problem.’”

Trump has said Muslim-Americans should register in a database and be tracked following the ISIS attack in Paris last month. He continued these remarks after the shooting in San Bernardino on Wednesday. Tashfeen Malik, the suspected female shooter who carried out the attack with her husband, reportedly pledged allegiance to ISIS.

In the interview, Trump refrained from speaking about a database, but expressed his support of heightened surveillance.

“If you have people coming out of mosques with hatred and with death in their eyes and on their minds, we’re going to have to do something,” he said. “You have people that have to be tracked. If they’re Muslims, they’re Muslims.”

The real estate mogul advocated for more profiling, referring to the one report that a neighbor of the shooters in San Bernardino feared telling anyone about suspicions packages arriving at the home of the shooters because she didn’t want to be racist. No other neighbors expressed suspicions.

“If they thought there was something wrong with that group and they saw what was happening, and they didn’t want to call the police because they didn’t want to be profiling, I think that’s pretty bad,” Trump said. “Everybody wants to be politically correct, and that’s part of the problem that we have with our country.”

However, Trump did not explain how profiling should be carried out. He also ignored the question about how the three million Muslims in Americans should view their place in the country, responding that the country has “a tremendous problem with radical Islamic terrorism.”

He added that the problem will get solved when President Barack Obama “gets the hell out” of office, making the typical Republican argument that Obama and other Democrats’ refrain from using the term “radical Islam” is part of the problem.

Trump explained that part of how his plan to end terrorism is targeting the families of terrorists.

“I would be very tough on families because the families know what’s happening,” he said. On exactly what he would do to the families, he said “I’m gonna leave that to your imagination.”

He added that he does not believe the sister of Syed Farook that she did not know anything about the attack beforehand, and she would be someone he would interrogate.

“I would go after a lot of people and find out whether or not they knew,” he said. “I’d be able to find out.”