The US Senate has inched closer to scheduling votes on limited gun control measures after the Florida nightclub massacre.
Democrats challenged Republicans on Thursday to defy the national gun lobby and vote for new restrictions.
Senator Chris Murphy and fellow Democrats seized control of the Senate floor for 15 straight hours demanding congressional action.
They ended their speeches before dawn, citing a Republican pledge to hold votes soon on measures to expand background checks on gun buyers and prevent people on US terrorism watch lists from buying guns.
The push for gun control legislation, which would be the first in the United States in more than 20 years, followed a gunman's slaughter of 49 people at a gay Orlando nightclub in the deadliest mass shooting in modern US history.
Democratic Senator Dianne Feinstein, whose proposal would allow the US attorney general to stop any terrorist suspect from acquiring a gun, told reporters the gun control votes would likely be held on Tuesday.
Republican presidential candidate Donald Trump has joined the gun debate, announcing on Wednesday he would meet with the National Rifle Association, the country's most powerful gun lobby, to talk about barring people who are on terrorism watch lists from buying guns.
Trump's intervention was praised as an apparent move to the middle by one of his most severe critics, Republican Senator Lindsey Graham, a former presidential candidate.
Democrats were deeply sceptical that Mr Trump's word signalled any sort of shift toward more Republican support for Democratic-backed gun control proposals.
"Donald Trump, like the Republicans, he's talking the talk but he ain't walking the walk," the Senate's No. 3 Democrat, Chuck Schumer, told a news conference.
"He is going to meet with the NRA ... What's he going to come out saying? 'Oh the NRA and I agreed we shouldn't have terrorists have guns,' but doing nothing about it," Mr Schumer said.
No formal deal was announced but Senate Republican aides said representatives were working on possible amendments to an appropriations bill funding the commerce and justice departments.
"We'll try again today to move forward with amendments from both sides and once there is an agreement to do so we'll update everyone," Senate Majority Leader Mitch McConnell, a Republican, said on the Senate floor.
He chastised Democrats for their 15 hours of speeches, calling it a "campaign talk-a-thon".