Homeland Security chief says there are no credible threats ahead of 9/11 anniversary

As the effort to resettle those who escaped Afghanistan during the U.S. military withdrawal, there are now more than 46,000 Afghan refugees in the United States, according to law enforcement sources. More than a dozen of them have shown up on terror watch lists, the sources said.

But Homeland Security Secretary Alejandro Mayorkas said the U.S. has protocols to remove anyone brought to the country who later turns out to be a threat. "We screen and vet individuals before they board a plane to the United States," Mayorkas told "CBS Evening News" anchor and managing editor Norah O'Donnell in an exclusive interview. "An individual who does not satisfy our screening and vetting protocols is not admitted to the United States. And if in fact, we learn information subsequently, we place those individuals in removal proceedings so that they are set to leave the United States as swiftly as possible."