In an interview with Mark Halperin and John Heilemann of Bloomberg, the Republican presidential frontrunner refused to rule out using tactical nuclear weapons in the war against ISIS.

“I’m never going to rule anything out—I wouldn’t want to say. Even if I wasn’t, I wouldn’t want to tell you that because at a minimum, I want them to think maybe we would use them,” he said.

Trump also said he’s open to tactics like waterboarding and monitoring American mosques in the fight. He also talked about respect, which he sees as one of the biggest problems facing the US right now.

A request for comment from the Trump campaign was not immediately returned.

“They have to respect us,” Trump said in the interview. “They do not respect us at all and frankly they don’t respect a lot of things that are happening—not only our country, but they don’t respect other things.”

As he often does, Trump specifically said that people don’t have respect for President Obama.

“The first thing you have to do is get them to respect the West and respect us. And if they’re not going to respect us it’s never going to work. This has been going on for a long time,” he said. “I don’t think you can do anything and I don’t think you’re going to be successful unless they respect you. They have no respect for our president and they have no respect for our country right now.”