WASHINGTON - Democratic lawmakers shut down the US House of Representatives Wednesday by staging a sit-in (dharna) on the House floor to demand a vote on gun control legislation.

Roughly 40 House lawmakers led by Congressman John Lewis demanded a vote on measures to expand background checks and block gun purchases by some suspected terrorists in the aftermath of last week's massacre in Orlando, Florida, that killed 49 people. It was the worst shooting in modern history.

"No bill, no break," shouted Democrats, who demanded that House Speaker Paul Ryan, R-Wis., keep the House in session through its planned weeklong recess next week to debate and vote on gun legislation. Lewis said action on gun violence is long overdue. "Where is our courage?" said Congressman Lewis of Georgia, who organised the impromptu sit-in. "Those who pursue common-sense improvement are beaten down. Reason is is put aside ... What is the tipping point? Are we blind. Can we see? ... Give us a vote! we came here to do our job!".

Congressman Ted Poe, a Republican, repeatedly banged his gavel to call the House into order, but the Democrats refused, and so he gaveled the House into recess.

House Minority Whip Congressman Steny Hoyer, a Democrat, suggested that could be a marathon recess. "Our people deserve to know where their representatives stand on this issue, just as they now do with their Senators," he said. "Led by civil rights hero (Congressman) John Lewis, we will be sitting-in until the House is allowed an opportunity to vote. This is an issue that ought to transcend party — it's about saving lives and keeping our communities safe."

Ryan spokeswoman AshLee Strong said, "The House cannot operate without members following the rules of the institution, so the House has recessed subject to the call of the chair."

Most of the demonstration, unlike last week's filibuster in the Senate, was not broadcast on C-SPAN television because the network does not display the House floor when it is in recess. But many lawmakers took to social media to post photos and video of the protest.

“The cameras may have been shut down, but we're still here,” Congressman Tony Cardenas, a Democrat, , tweeted.

Democratic Leader Nancy Pelosi of California went to the floor and called for a moment of silence as some held hands and continued chanting.

“We cannot let another moment of silence happen on the House floor without acting," Pelosi said.

Over at the White House, Press Secretary Josh Earnest said House Democrats are “are showing the kind of frustration and even anger that people around the country have.”

“What Democrats are asking for is neither radical nor controversial,” he said, citing polls showing that expanded background checks are favoured by large majorities of people, including gun owners.