Incoming White House chief of staff Reince Priebus said creating a Muslim registry is not part of president-elect Donald Trump’s plan, but his team is working on a way to prevent radicalized terrorists from entering the country.

However, Priebus said he would not rule anything out.

"Look I'm not going to rule out anything," Priebus said in an interview at NBC’s ‘Meet the Press.’ "We're not going to have a registry based on a religion. But what I think what we're trying to do is say that there are some people, certainly not all people ... there are some people that are radicalized. And there are some people that have to be prevented from coming into this country."

He said Trump’s administration would put sctricter screening systems in place before immigration could be considered. He defended Trump’s stance on the matter, saying it is “consistent with bills in the House and the Senate” requiring a better vetting system from people who come from places that harbor and train terrorists.

“Where systematic terrorism is taking place, where countries are harboring or in places where countries are harboring and training terrorists, we’re going to temporarily suspend immigration from that country, or region, until a better vetting system is put in place,” Priebus explained on CNN’s ‘State of the Union’ on Sunday.

He commented on a statement released by Gen. Michael Flynn, who will sit as Trump’s national security adviser, on Twitter earlier this year that “fear of Muslims is rational.” Priebus said Trump and his team don’t believe in “religious tests.”

He said that while they will not give a blanket judgment on Muslims, there are certain Muslims that people do fear. And these are the ones that need to be kept out.

“When a better vetting system is put in place, then those radical folks … they will not be allowed in, but then others will be allowed in. But only until that is done,” Priebus said.

Trump earned criticism when he said, after the San Bernardino shooting last December, that he would ban Muslims from entering the U.S. “until our country’s representatives can figure out what’s going on.”

Priebus also said the Trump administration will block federal funds from “sanctuary cities” that want to protect immigrants by not complying with immigration laws.

“In recent years, local governments across the country fought back against federal immigration enforcement by calling themselves sanctuary cities,” he said. “Trump made them a focus on the campaign trail, pledging to block funding for cities that take that tack.”