Following the rapid rise of the Taliban to control of Afghanistan, even if terrorist threats reemerge from that country the U.S. already has safeguards in place to protect itself and doesn’t need to add new security mechanisms, Homeland Security Secretary Alejandro Mayorkas said on Thursday.

Mayorkas, speaking at the National Press Club, pointed to concerns about the “threat landscape” posed by the Taliban takeover in Afghanistan and whether “new processes and systems” need to be layered in in case the Al-Qaida terrorist group becomes prominent again in that country, and said that “once again, the answer is no because we have never dismantled or weakened the systems that we built then. We have only added to them so that we are as dynamic as the threat landscape we confront and that we are dedicated to address in the safety and security of our homeland.”

President Biden’s decision to essentially stick with the plan of former President Trump to withdraw U.S. forces from Afghanistan led to the quick collapse of the country’s government and military, forcing the U.S. to reinsert military forces to aid in a mass evacuation of American citizens and partners from the country in August.

It was the Taliban’s refusal in 2001 to kick Al-Qaeda out of the country that led then President George W. Bush to send the U.S. military in to knock out the Taliban and hunt down the terrorist group and its leader, Osama Bin Laden. With the Taliban back in power, concerns have flared that Afghanistan will become a haven for terrorists willing to harm the U.S. and its interests.

During the evacuations from Hamid Karzai International Airport in Kabul, an Islamic State suicide bomber killed 13 U.S. troops and dozes of Afghanis.

“The biggest concern with Afghanistan has always been that it’s a breeding ground for terrorists if we don’t have a presence there and don’t have intelligence,” Rep. John Katko (R-N.Y.), ranking member on the House Homeland Security Committee, said during a Fox News program on Aug. 31. “The terrorists are already there. ISIS already killed our soldiers. ISIS-K is there. Al-Qaeda is there. Prognosticators all over the United States who know the intel and know the homeland security issues like I do are very worried about homeland attacks coming in the near future.”

During the Press Club event, Mayorkas was asked about reports that some ISIS members may have been evacuated with Afghan refugees brought to the U.S. and what is being done to ensure terrorists aren’t hiding among the evacuees.

Mayorkas said there is no information that Islamic State terrorists have entered the U.S. as part of the refugee transfers. He described the screening and vetting process employed by a number of agencies for the refugees as “multilayered” to weed out potential threat actors.

“We screen and vet individuals before they board planes to travel to the United States and that screening and vetting process is an ongoing one and multilayered,” he said. “We work with the law enforcement, counterterrorist and intelligence communities to achieve that vetting.”

The vetting includes obtaining biographic and biometric data from individuals, Mayorkas said. The Department of Homeland Security has deployed about 400 personnel and equipment to help them to overseas locations where Afghan refugees first arrive after departing Kabul to capture the biographic data and fingerprints to be searched against the various federal government watchlists to “see whether there is any information that we have that would give us reason to be concerned. That is really the substance of vetting,” he said.