Ben Cardin said the staff member who has been linked to the clip was "no longer a Senate employee".

The Maryland Democrat told reporters: "I was angry, disappointed. It's a breach of trust. All of the above."

No charges have been filed, according to US media. The BBC has contacted US Capitol Police for comment.

The police department tasked with protecting Congress has told US media it was looking into the matter.

The Daily Caller reported on Friday that the video showed a congressional aide having "sex with an unknown man in the Senate hearing room" and that it was posted in a private group for gay men in politics. It is unclear when it took place.

The tape appeared to have been filmed in a deserted Hart Senate Office Building room 216, according to Politico. The room has hosted blockbuster hearings, including the 9/11 Commission and Supreme Court nominations.

Senator Ben Cardin said he was "disappointed"

The BBC has not independently verified the video or confirmed the identity of anyone involved.

On Monday, Mr Cardin was asked by reporters how an aide would have been able to access the Senate hearing room.

"These are personnel issues," said the senator, who is set to retire at the end of his term.

"Over the weekend when I learned about it, I made sure that... the appropriate steps were taken," he added.

Senator Amy Klobuchar, a Minnesota Democrat, told reporters that the aide in question had been fired.

By Madeline Halpert
BBC News