Republicans dismiss gun-control protest as publicity stunt
Republicans have dismissed as a "publicity stunt" a continuing sit-in protest over gun laws by Democrats in the US House of Representatives.
Speaker of the House Paul Ryan said the protesters were more interested in headlines than tackling gun violence.
The protest comes in the wake of the recent shootings in Orlando, the deadliest in modern US history.
Republicans adjourned the chamber early on Thursday with no more votes until after the 4 July holiday.
Before closing the lower house of Congress, they pushed through several unrelated measures, including a bill to provide funds to fight the Zika virus outbreak.
About a dozen Democrats remained as the protest stretched into the 22nd hour.
Entrenched divide: Anthony Zurcher, BBC North America
Depending on one's perspective, the sit-in was either a shameless publicity stunt in advance of a dangerous piece of legislation or the purest expression of democracy and civil disobedience since the 1960s.
But as Democrats chanted, waved signs and sang in protest, there was no debating it was a historic break with congressional traditions that has little precedent in modern times.
The display seems unlikely to alter the dynamic in a House dominated by conservatives overwhelmingly opposed to new gun regulations. If anything, after a night of sniping and rancour across the partisan divide, the two sides may be even more deeply entrenched.
Republicans view the use of the terrorist watch list to prevent firearm purchases as giving the government the power to suspend due process with next to no judicial oversight. Democrats counter that it's a common-sense first step towards addressing rampant gun violence.
Both see their position as guided by principles to be defended to the end, a prospect that makes this dispute likely to be settled only at the ballot box in November.
"While the Americans don't always expect us to win, they do expect us to fight," said Democratic Rep Al Green.
Scores of gun-control advocates and protesters remained fixed outside the Capitol to support the demonstration.
At the scene - Ashley Gold, BBC News, US Congress
About two dozen gun control advocates were gathered outside the Capitol building on Thursday morning, tired but intended to stay put while a dwindling group of Democratic House members continued a sit-in inside.
Honora Laszlo, from Arlington, Virginia was touched by gun violence at 15, when her mother's best friend was killed by her estranged husband at age 47.
In another instance, her close family friend was shot to death in front of his family over an argument over baseball.
Most people here say the Newtown school massacre in Connecticut, in which 26 children and adults were killed, is when they got involved in gun control advocacy, she said.
But for Ms Laslzo, it was something different. She said the killing of Trayvon Martin in Florida was indicative of National Rifle Association "culture", and that's what compelled her to act.
Ms Laslzo said the time has come to "make trouble" to force legislation on gun control and it is no longer acceptable to quietly ask for change.
The Democrats' protest follows the gun attack on 12 June, when a man claiming allegiance to the so-called Islamic State group, Omar Mateen, killed 49 people at the Pulse club in Orlando, Florida.
House Republicans echoed their leader's comments and branded the act as a publicity stunt.
Representative Kevin Cramer said: "I have no objection to them making fools of themselves on TV."
Mr Ryan told CNN he would not bring a gun-control vote in the House.
"They know that we will not bring a bill that takes away a person's constitutionally guaranteed rights without... due process," he said.
Many Democrats filmed the raucous scenes from the overnight protest, streaming speeches live via phones despite breaking rules on broadcasting.
The transmissions via Periscope and Facebook Live were taken up by the C-Span network, which provides continual coverage of Congress. One Democrat congressman, Scott Peters, who provided a feed, said the sit-in was breaking rules anyway.
Democrats stormed the House floor Wednesday morning, with some 168 House members (out of 188) and 34 senators (out of 44) on the floor and in the aisles by evening.
Mr Ryan tried to restore control with a recess, banging his gavel and ignoring the Democrat shouts of "Shame! Shame!" before he left the podium.
Democrats began singing "We shall overcome" and held up the names of gun attack victims.
Some Democratic representatives brought in sleeping bags, pillow and blankets, while Senator Elizabeth Warren offered a brief respite with doughnuts for colleagues.
But Democrats shouted their new campaign slogan "No bill, no break!" and some remained on the floor, streaming speeches live. Representative Eric Swalwell told the BBC that the lawmakers would stay through the night.
The BBC's Laura Bicker in Washington says the protest follows years of Democrat frustration at being unable to pass stricter gun control measures.
She says that although 100 bills have gone before Congress in the past five years and all have failed, this is an election year and Democrats are making it clear to the electorate that if they want change, they know which way to vote in November.
A similar incident occurred in 2008, when Republican lawmakers took to the House floor to protest a lack of vote on an energy bill.
However, the difference was the Republican-led protest took place during a summer recess, which meant Democrats did not push through any legislation during the demonstration.
Guns in the United States
mass shootings in 2016
people have been killed in gun incidents this year
31% of US households have a firearm
357 million firearms in the US (estimated)
101 firearms for every 100 people (estimated)
23 million background checks were carried out by the FBI in 2015
The sit-in is being led by congressman John Lewis, a veteran of the civil rights movement of the 1960s.
"What has this body done [to respond to the violence]?'' Mr Lewis asked.
"Nothing. We have turned a deaf ear to the blood of innocents. We are blind to a crisis. Where is our courage? How many more mothers... and fathers need to shed tears of grief?"
President Barack Obama took to Twitter to thank Mr Lewis "for leading on gun violence where we need it most".