Homeland Security Secretary Kirstjen Nielsen on Sunday did not deny reports that President Donald Trump is considering sealing the U.S.-Mexico border, even to asylum seekers, via an executive order. Such an action would be contrary to U.S. and international law requiring that asylum seekers be given an opportunity to make their case.

“On what legal basis could he do that?” Fox News Sunday’s Chris Wallace asked Nielsen, after noting a report that Trump could order the border closed “even to those seeking asylum.”

Nielsen didn’t answer directly. “This caravan is not getting in. There’s a legal way to enter this country. Those who choose to enter illegally will be stopped.”

Multiple outlets reported this week that Trump is considering sealing the southern border to asylum seekers via an executive order citing his national security authority, despite Trump himself admitting he has no proof to back up his claims that criminals and terrorists are among those asylum seekers and migrants headed toward the border. In any case, the caravan is currently about 1,000 miles away from the U.S.-Mexico border.

Wallace pressed: “On what basis can you say that this caravan poses a national security threat?”

“We have a crisis at the border right now,” Nielsen responded, before adding, referring to the number of people apprehended daily while crossing the southern border: “We essentially see caravans every day with these numbers.”

“I think what the President is making clear is every possible action, authority, executive program is on the table to consider to ensure that it is clear that there is a right and legal way to come to this country, and no other ways will be tolerated,” she said.

Wallace pressed again: “We’re talking, in many cases here, about women, about children, about babies. How do they threaten national security?”

After pointing out that the caravan “isn’t a ticketed event,” Nielsen asserted: “This is about the rule of law, this is about understanding who is in the flow. And Chris, I cannot tell you, as secretary of Homeland Security, that I know every person in this flow.”

“What I do know,” she continued, “is that we stop 3,000 people a year who have travel patterns similar to terrorists attempting to come in the southwest border.”

Reached for comment, a DHS spokesperson did not clarify what “travel patterns similar to terrorists” are.

Nielsen also asserted that “in general, we stop, across the United States, 10 known or suspected terrorists a day from getting into the United States.”

That appeared similar to claims made by Vice President Mike Pence and White House press secretary Sarah Huckabee Sanders in recent days. Pressed for details about the statistic, a DHS official gave TPM a different, more general version, that “On average last year, DHS prevented 10 individuals tied to terror — known or suspect terrorists — each day from traveling or attempting to travel to the United States.” The official said “there is no report to link to” that backs up the assertion, just unpublished “DHS data.”