CBS News’s Margaret Brennan pressed President-elect Trump’s new border czar Tom Homan over the next administration’s mass deportation plans.

Homan joined Brennan on “Face the Nation” on Sunday, where he was questioned about Trump’s plans for the largest deportation operation in history. Brennan asked the former Immigration and Customs Enforcement director what is a number of deportations that the administration would consider a success.

Homan directed the conversation to the Biden administration, who took action earlier this year to limit the number of asylum seekers entering through the U.S.-Mexico border. Homan argued that 80 percent of the Biden administration’s deportation numbers are from Border Patrol arrests that were moved back across the southern border.

“They weren’t interior enforcement arrests,” he said, adding the Biden administration is “playing a numbers game.”

Brennan noted that it’s still a higher number than when Trump was in office the first time. She pressed Homan on if success would come from arresting and deporting people already within the United States, in addition to sealing off the southern border.

“You can compare the number of deportations under Trump versus Biden,” he said. “When you consider a 45-year low in crossings, the number of deportations’ going to be lower because we don’t have that population to process and deport.”

Brennan continued pressing Homan, questioning what the Trump administration’s measure of success for its day one deportation plans will be.

Neither Trump nor Homan have offered concrete plans for how they intend to deport millions of people. Trump has signaled he would use the U.S. military to carry out his plans, but immigration advocates warn the lofty goal will be costly and harmful to the country.

Homan said Sunday that Trump will be focusing on public safety threats, including migrants who have committed crimes or intend to cause national harm.

Brennan questioned how the administration will find criminals and what a deportation plan would look like.

Homan said ICE knows where “some” are but placed blame on Department of Homeland Security Secretary Alejandro Mayorkas for the lack of arrests. He also criticized sanctuary cities, places that have said they will not target migrants, for putting communities at greater risk.

Brennan questioned the logistics of deporting many people, particularly if other countries aren’t willing to accept them.

“We’re hoping that President Trump will work with Venezuela and like he did with Mexico and El Salvador and get these countries to take them back,” Homan said. “If they don’t, they’re still gonna be deported. They’re just gonna be deported to a different country.”

“We gotta put the safety of the American people first,” he continued. “We’ve had too many young women murdered and raped and burned alive by members of Venezuelan gangs. They need to be a priority under this administration. They’re gonna be a priority starting day one, and they will be deported.”

Brennan concluded the interview, noting that the country will “stay tuned for the details.”