(Bloomberg) -- US Senator Elizabeth Warren urged the Department of Defense to rein in the use of Starlink in Russia and other unauthorized regions, saying the SpaceX-owned satellite business poses a “serious national security threat” to the US and its allies. 

“SpaceX must make every attempt to ensure its Starlink devices and service are obtained and operated in full compliance with US law — but reports suggest it may not be doing so effectively,” Warren wrote in a letter dated May 6 addressed to Defense Secretary Lloyd Austin.

The letter follows a March investigation by Bloomberg News, which first revealed the extent to which Elon Musk’s satellites are being used in countries around the world where it is illegal to operate Starlink terminals, including in territories ruled by repressive regimes. The ease of smuggling the kits and the sheer availability of Starlink on the black market indicates its misuse remains a systemic global problem and has raised questions about the company’s control of a system with expansive national security dimensions. 

Read more: Elon Musk’s Starlink Terminals Are Falling Into the Wrong Hands

Following the investigation, as well as a similar report weeks later in The Wall Street Journal, Starlink sent emails to account holders warning “if you are operating your Starlink Kit in an area other than areas designated as — available — on the Starlink Availability Map, we would like to remind you that this is in violation of the Starlink terms and starting April 30th, 2024, you will be unable to connect to the internet,” according to communications seen by Bloomberg and first reported by the Journal.

As of last week, the Starlink service was still operating in multiple unauthorized regions, defying warnings, according to Bloomberg reporting. 

On Monday, Senator Warren, a Democrat representing Massachusetts, said she was calling on the defense department to ensure any US contractors are “held accountable for any expropriation of their technology by hostile actors.” She requested answers from the Defense Department on its contractor relationship with and oversight power over SpaceX by June 5.

SpaceX didn’t immediately respond to a request for comment.

New from Bloomberg: Get the Business of Space newsletter, a weekly look at the inside stories of investments beyond Earth.

--With assistance from Loren Grush and Steven T. Dennis.

©2024 Bloomberg L.P.