Under orders from the Trump White House, the Transportation Security Administration has begun transferring more than 600 of its workers from airport security to enforce immigration policies along the southern border.

It will have no effect on aviation security,” TSA Administrator David Pekoske told the House Committee on Oversight and Reform, during a hearing that “bristled with partisan contention,” reports the Washington Post.

The committee chairman, Rep. Elijah Cummings (D-MD), questioned Pekoske’s claim, as well as the administration’s priorities.

Today, nearly 20 years after the terrible attacks of September 11, 2001, we are holding this hearing to examine why urgent warnings from independent auditors about security vulnerabilities at the [TSA] have been languishing for years without being resolved,” said Cummings, according to the Post.

“Unfortunately, this is part of a larger trend,” Cummings added. “TSA also has failed to address warnings from the inspector general. As of this month, 37 recommendations made by the inspector general from 12 reports on aviation security remain open and unfulfilled. Several of those are many years old.”

Pekoske and committee Republicans said the U.S. faces a “crisis” on the border.

“Border security is national security. This is a crisis,” Pekoske said. “I have to balance off the risk at the southern border with the need to keep airports staffed.”

Word of the TSA transfers came on the same day that John Sanders, acting commissioner of U.S. Customs and Border Protection, revealed he will join many other Trump officials departing the administration. Sanders has had the job for just two months.

Cummings said about 370 TSA security officers and federal air marshals have already been diverted to the border, with another 294 TSA employees due to follow soon. The TSA has a total workforce of 63,000.

The administration is not helping aviation security. They are harming it,” Cummings said. “Let me put this quite starkly: On the one hand TSA has dozens of security vulnerabilities that have languished for years, but the Trump administration is asking Congress for 700 more TSA screeners to handle huge increases in air travel.

“Yet on the other hand, the Trump administration is taking more than 350 of these critical TSA employees, diverting them away from their primary responsibilities . . . and sending them to the southern border.”

According to the Post, the TSA screens about 2 million air passengers on more than 25,000 flights every day at about 440 airports nationwide.