Members of the centre-left Democratic Party said they will keep fighting for gun control after a 16-hour sit-in at the US House of Representatives failed to force a vote on tougher laws, a move the conservative Speaker of the House called "a publicity stunt."
"We will continue to fight," vowed Representative John Lewis, a veteran legislator well known for his role in championing civil rights for African Americans in the 1960s.
Lewis and several dozen lawmakers had occupied the floor of the chamber and said they wouldn't leave until Speaker of the House Paul Ryan, a Republican, scheduled a vote on a measure to keep people on the terrorist no-fly list from buying guns.
The move came amid demands for action on tougher gun laws following the latest mass shooting by a US-born attacker pledging allegiance to terrorist militia Islamic State at a gay nightclub in Orlando, Florida, last week.
But the centre-right Republicans, who control the House, forced the chamber to go into recess after holding a vote that passed along party lines shortly before 3 am (0700 GMT).
Unlike the Senate, there is no formal mechanism for lawmakers in the House to hold the floor indefinitely.
"How many more mothers, how many more fathers need to shed tears of grief before we do something? We were elected to lead, Mr Speaker," Lewis said in earlier remarks during the sit-in.
In an interview with CNN, Ryan called the action by the Democrats, "nothing more than a publicity stunt."
"This bill was already defeated in the United States Senate," the Speaker of the House said, justifying Republican opposition to the bill by adding: "We are not going to take away a citizen’s constitutional rights to due process."
Ryan further denied that the issue was gun control, but rather terrorism.
"Let’s find out what we need to do to prevent future terrorist attacks. And if a person is on a terror watch list and they go try to buy a gun, we have procedures in place to deal with that."
Omar Mateen, the perpetrator of the Orlando shooting, had twice been investigated and cleared by the FBI for alleged links to terrorism. He was not on any federal watch list or under surveillance. Federal authorities say the weapons he used were legally purchased.
The upper Senate on Monday failed to pass a series of tougher gun laws aimed at preventing suspected terrorists from getting guns.
Nancy Pelosi, leader of the minority Democrats in the lower House, however called for a vote on bipartisan legislation to keep those on the watch list from buying guns and for stricter background checks on gun buyers.
White House spokesman Josh Earnest called the sit-in a reaction to frustrations after years of inaction on gun laws.
Democrats were "showing the kind of frustration and even anger that people around the country have about the inability of the Republican-led Congress to take common sense steps that protect the American people," Earnest said.
"I crossed a bridge, it didn't take us one time. It took us three times," Representative Lewis said, drawing an analogy to repeated efforts to stage a march across a bridge near Selma, Mississippi that led to violent clashes in the 1960s and became symbolic of the fight for voting rights in the US.