Senator Elizabeth Warren has demanded an investigation after Musk acknowledged he had blocked Ukraine from extending the private Starlink satellite network for an attack on Russian warships near the Crimean coast after having a cosy chat with his bestie Tsar Vladimir Putin.

Warren said that Congress needs to investigate what's happened and whether it had adequate tools to make sure foreign policy was conducted by the government and not by one billionaire.

Musk, the chief executive officer of SpaceX, is expected to be among the technology industry chiefs to attend a closed-door summit with senators at the Capitol later today.

Warren, a member of the Armed Services Committee, said she wants the Defence Department to look into its contractual relationship with the company.

Armed Services Chairman Jack Reed, a Rhode Island Democrat, also said he was concerned about the issue, given that governments traditionally have controlled satellites and presidents decide what to do with them.

He said there have been very positive developments with SpaceX reducing the cost of access to space, including for national security launches, "but he can't be the last word when it comes to national security," he said of Musk.

Musk posted on X that there was an emergency request from government authorities to activate Starlink to Sevastopol.

"The obvious intent being to sink most of the Russian fleet at anchor. If I had agreed to their request, then SpaceX would be explicitly complicit in a major act of war and conflict escalation."

Musk later expressed his support for the US: "I am a citizen of the United States and have only that passport. No matter what happens, I will fight for and die in America. The United States Congress has not declared war on Russia. If anyone is treasonous, it is those who call me such."