WASHINGTON (Reuters) - The leaders of a U.S. House of Representatives panel have called on top Chinese telecom companies to detail any links to the Chinese military and government, citing national security concerns posed by the companies' U.S. presence.

Representative Raja Krishnamoorthi, the top Democrat on the House Select Committee on China and the panel's chair, Republican John Moolenaar, asked China Mobile, China Telecom and China Unicom to answer a series of questions by March 31, according to letters seen on Friday by Reuters.

The lawmakers raised concerns the firms could exploit access to American data through their U.S. cloud and internet businesses by providing it to Beijing, citing a 2024 Reuters report that revealed a Commerce Department investigation into the matter.

"China Telecom's ongoing U.S. operations - particularly in internet backbone exchanges and cloud computing environments - could ... allow unauthorized data access, espionage, or sabotage by the Chinese Communist Party," the lawmakers wrote in one of the letters to the firms seen by Reuters.

The firm's "documented connections to (Chinese) intelligence raise urgent national security questions in light of the Chinese government's increasingly aggressive attacks on U.S. telecommunications networks," they added.

The companies did not immediately respond to requests for comment.

The letters show growing bipartisan concern about the Chinese telecoms' U.S. footprint following a series of high-profile Chinese-led attacks on American telecoms infrastructure.

Salt Typhoon, described by the top Democrat on the Senate Intelligence Committee Mark Warner as "the worst telecom hack in our nation's history," compromised sensitive data of millions of Americans.

Volt Typhoon, tied to China's Ministry of State Security, is waging what the FBI calls China's "most significant cyber-espionage campaign in history," the letters add. Beijing has denied responsibility.

China Telecom, China Mobile and China Unicom have long been in Washington's crosshairs. The Federal Communications Commission denied China Mobile's application to provide U.S. telecommunications service in 2019 and revoked China Telecom and China Unicom's authorizations in 2021 and 2022.

In April 2024, the FCC went further and said it was barring the companies from providing broadband service once new rules took effect on net neutrality. But the net neutrality rules were blocked by a court.

Nothing prevents Chinese telecoms from providing cloud services and routing wholesale U.S. internet traffic, which gives them access to Americans' data, the lawmakers said.