President Donald Trump spoke for 40 minutes with three leading senators Wednesday about expanding background checks, keeping alive the Senate’s long-running gun negotiations with the White House for at least one more day.

Trump is expected to be briefed on Thursday by White House officials on his options, according to two GOP officials familiar with the matter. And Sens. Joe Manchin (D-W.Va.), Chris Murphy (D-Conn.) and Pat Toomey (R-Pa.) said that Trump could signal to the Hill what package he could support as soon as Thursday.

The senators described Trump as engaged and inquisitive on the speakerphone with them Wednesday as they made a last-ditch bid to get the president behind expanding background checks to cover private sellers on the Internet, advertisements and gun shows. Trump has been extraordinarily reluctant to commit to any specific piece of legislation, but the senators said he’s doing enough to keep their hopes alive.

“We’ll know hopefully by tomorrow if there’s something we can agree on, and once we agree on something we’re going to hold to it and fight for it,” Manchin said. Trump “can support something we all can agree on is what I took out of it.”

“We’re getting to the witching hour and we’ll know soon within the next day or two about whether the White House is willing to put a substantive background checks bill on the table,” Murphy said.

But Toomey, who is lobbying skeptical members of his own party to support a new version of legislation he wrote with Manchin in 2013, was more cautious on both the timeline and the president’s stance. Trump said Wednesday that they are “going to take a look at a lot of different things.”

“He did not make a commitment to support any particular bill or any particular thing but he did strongly convey an interest in doing something meaningful,” Toomey said. “There was a discussion about having a step forward one way or another tomorrow but that’s not carved in stone.”

Congressional and administration officials could not offer a firm timeline for action from the president. Sen. John Cornyn (R-Texas) said he expects something this week, but a White House official insisted that no date had been selected for the gun rollout and that no decision had been made on when the proposal will come out.

The confusion over the timeline only further muddled what’s been a wide-ranging debate but one that has yet to make any concrete progress. Trump met with the top GOP congressional leaders at the White House on Tuesday afternoon, but although firearm legislation was discussed, neither firm policy nor rollout dates were decided upon.

“When that happens I’m not sure. They were driving toward the end of the week,” said Senate Majority Whip John Thune (R-S.D.), who attended the meeting. “There is an amount of inertia toward trying to get to a plan but I don’t want to make any guarantees about when it comes.”

While other senators like Lindsey Graham (R-S.C.) are working on providing grants for states to expand red flag laws and Susan Collins (R-Maine) has legislation to crackdown on straw purchasers, the group of three senators made clear to the president that any package should center around background checks.

“We all agree people in those categories should not have firearms. This is a commonsense way to make it much more difficult for those folks to get it. That’s the case that I made to the president,” Toomey said of the conversation. Officials from the Justice Department were also on the call, senators said.

Republicans have been loath to expand background checks in previous attempts, and just Toomey and Collins remain as GOP supporters of the background checks bill from 2013. But members of both parties see an opportunity for Trump to take the lead and push a bill past the Senate’s 60-vote threshold -- and potentially reinvigorate a debate that’s fallen along partisan lines for years.

“If this is a compromise, it’s going to be a compromise. It’s going to have some Republican ‘no’ votes and some Democratic ‘no’ votes,” Murphy said. “If I end up agreeing to something that’s not … universal background checks, that’s going to be a heavy lift on the democratic side.”

The House has passed a universal background checks bill but the proposal being discussed is narrower, offering more exemptions for friends and family to do gun sales with no background check.

Anita Kumar contributed to this report.