Massachusetts U.S. Rep. Seth Moulton says he will not participate in a moment of silence on the House floor after 50 people were killed in Las Vegas and more than 400 others were sent to area hospitals in the deadliest mass shooting in American history.

The Democratic congressman, along with his Bay State colleague Katherine Clark, also did not participate in a moment of silence after a mass shooting in Orlando claimed the lives of 49 people in June 2016. The two joined other Democratic representatives to walk out on the moment of silence in a protest over a lack of gun control.

Moulton wrote on Twitter, "As after #Orlando, I will NOT be joining my colleagues in a moment of silence on the House Floor that just becomes an excuse for inaction."

He added, "Now is not a moment for silence; it's a time for action."

Moulton later followed up with a challenge to House Speaker Paul Ryan, asking "how many Americans have to die before you do your job? Allow us to have a debate and a vote. You're letting America down."

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