Chairman Jack Reed said in a statement Thursday the reports on the use of Starlink exposed “serious national-security liability issues and the committee is engaged on this issue.”

“The committee is aggressively probing this issue from every angle,” he said.

Musk’s SpaceX also has become a major US contractor, launching spy satellites for the Defense Department and operating the Starlink network. The company didn’t immediately respond to a request for comment.

Reed said the committee will look at the broader satellite market, government contracting and “the outsized role Mr. Musk and his company have taken here.”

Reed and other senators have questioned why the decision wasn’t made by a government official.

“Neither Elon Musk, nor any private citizen, can have the last word when it comes to U.S. national security,” Reed said.

Other Democratic senators on the committee, including Jeanne Shaheen of New Hampshire and Elizabeth Warren of Massachusetts, have pressed the Defense Department for answers on why it was Musk — and not a US government official — deciding when Ukraine can use the satellite network.

Shaheen and Warren plan to send a letter to Defense Secretary Lloyd Austin asking for details on Starlink and Musk’s work in Ukraine, said a congressional aide who asked not to be named to discuss internal deliberations. The panel is not yet launching a formal investigation but rather gathering information, the aide said.

Shaheen said in a brief interview she has asked administration officials during classified briefings about control over the use of Starlink in Ukraine and has not gotten answers.

At the time of Ukraine’s request last year, Musk wasn’t getting any US funding for Starlink’s operations in Ukraine, although it currently is supported with Pentagon funds.

— With assistance by Loren Grush