WASHINGTON (Reuters) – U.S. Democratic Senator Chris Murphy ended a blockade of the Senate after nearly 15 hours on Thursday, saying Republicans agreed to hold votes on measures to expand background checks and prevent people on U.S. terrorism watch lists from buying guns.

Democrats stalled Senate proceedings on Wednesday in a bid to push for tougher gun control legislation following Sunday’s massacre of 49 people at a gay nightclub in Orlando, Florida, and spoke on the Senate floor through out the night.

Republicans, who currently have a 54-person majority in the Senate, have over the years blocked gun control measures, saying they step on Americans’ right to bear arms as guaranteed under the U.S. Constitution.

“When we began there was no commitment, no plan to debate these measures,” Murphy, of Connecticut, said during the 15th hour of the filibuster early on Thursday.

He said Democrats were given a commitment by the Senate’s Republican leadership that votes would be allowed on two measures on preventing gun sales to people on terrorism watch lists and expanding background checks.

“No guarantee that those amendments pass but we’ll have some time to … prevail upon members to take these measures and turn them into law,” Murphy said.

With Republicans and the National Rifle Association gun lobby under pressure to respond to the massacre, presumptive Republican presidential nominee Donald Trump said on Wednesday he would meet with the NRA to discuss ways to block people on terrorism watch or no-fly lists from buying guns.

The Senate had began discussions on legislation to ban firearm sales to the hundreds of thousands of people on U.S. terrorism watch lists. The Orlando gunman, who carried out the worst mass shooting in modern U.S. history, had been on such a list.

Republican Senate Majority Leader Mitch McConnell urged senators on Wednesday to offer ideas on how to prevent another attack like the one in Orlando.

Late on Wednesday Senate Democratic leader Harry Reid said negotiations “were little more than a smokescreen by Republicans trying to give themselves political cover while they continue to march in lock-step with the NRA’s extreme positions.”

If Congress was to pass a gun control measure, it would mark the first time in more than 20 years that lawmakers agreed on how to address the hot-button issue. A ban on semi-automatic assault weapons, such as the one used in Orlando, had gone into effect in 1994 and expired 10 years later.

(Reporting by Susan Cornwell; Writing Mohammad Zargham; Editing by Bill Trott)