Attorney General Jeff Sessions is urging Congress to "promptly" reauthorize a section of the Foreign Intelligence Surveillance Act scheduled to expire at the end of the year.

Director of National Intelligence Dan Coats also signed the letter, addressed to House Speaker Paul Ryan, R-Wis., House Minority Leader Nancy Pelosi, D-Calif., Senate Majority Leader Mitch McConnell, R-Ky., and Senate Minority Leader Chuck Schumer, D-N.Y.

In the letter, addressed Sept. 7 but made public on Monday, Sessions and Coats say Congress must "promptly reauthorize, in clean and permanent form" Section 702 of FISA.

FISA is the legal basis for U.S. surveillance programs, and has faced scrutiny lately after it was revealed Section 702 of the law allowed for the capture of conversations President Trump and his transition team had with foreign officials.

Section 702 of FISA "allows the Intelligence Community, under a robust regime of oversight by all three branches of government, to collect vital information about international terrorists, cyber actors, individuals and entities engaged in the proliferation of weapons of mass destruction and other important foreign intelligence targets located outside the United States," Sessions and Coats wrote.

They added: "Reauthorizing this critical authority is the top legislative priority of the Department of Justice and the Intelligence Community. As publicly reported by the Privacy and Civil Liberties Oversight Board, information collected under one particular section of FAA, Section 702, produces significant foreign intelligence that is vital to protect the nation against international terrorism and other threats."

In June, President Trump's homeland security and counterterrorism adviser Tom Bossert penned an op-ed in the New York Times also urging Congress to reauthorize FISA before its sunset on December 31.