Amid mixed signals from the White House, Sen. Chris Murphy said Friday that prospects for new gun control measures in Congress remain uncertain.

Speaking at separate press conferences Friday at the state Capitol, Murphy and Sen. Richard Blumenthal reinforced their commitment to “common sense” gun laws, and stressed a need for President Donald Trump’s support Friday morning.

Murphy believes congressional Republicans will not act on meaningful reform, including expanded background checks and red flag statutes, unless the president gives firm public support for the legislation. Blumenthal said that only Trump’s support will motivate Republicans to vote for the gun law reform he has in mind.

“The only way that we pass a bill in the Senate is if there is a proposal with words on a piece of paper that the president says he’s for, and says it for more than 24 hours at a time,” Murphy said.

Murphy’s comments come after the president on Wednesday said he is discussing gun law reform with Republicans, Democrats and the NRA. The White House expects to release proposals soon regarding expanded background checks and other reforms.

Because of what he sees as mixed signals from the Trump administration as to which reforms the president would support and to what extent, Murphy said he is not overly confident that reform will come soon.

“I am skeptical that these efforts are going to bare fruit,” Murphy said on Friday. “I think it’s very hard to negotiate with this White House when the president’s public positions seem to change by the day.”

The president called Murphy last weekend in response to the mass shootings in El Paso, Texas, and Dayton, Ohio, that left more than 30 dead, and expressed support for meaningful reform. Murphy said he was surprised to receive the call but that the president seemed to understand his linchpin role in Republican support for gun law reform.

“The president called me and told me personally that he was indeed serious about moving forward together on what he called ‘meaningful background checks legislation,’ ” Murphy said. “The president told me that he knew that Republicans in the Senate wouldn’t support it unless he supported a background checks measure.”

Trump told reporters on Wednesday that he has also spoken with the NRA this week about “loopholes in background checks."

“Well, what we’re doing is I want guns to be in the hands of people that are mentally stable. And those people, I want them to easily be able to get a gun. But people that are insane, people that are sick up here, I don’t want them to be able to get a gun,” Trump said Wednesday on the White House lawn.

Murphy said he has not spoken directly to Trump since their initial phone call, but that he has been in contact with top legislative aides in the White House as recently as Thursday night. Murphy said he wants to work with the White House on a proposal that meets his qualifications for meaningful gun reform that also has the president’s support.

Murphy cautioned against the NRA’s involvement with gun reform talks. Murphy said he made it clear to the president that any “meaningful” reform would not be supported by the gun lobby.

He remained hopeful that he could work with the White House to find a compromise.

“I believe that the White House is still committed to trying to work on a comprehensive anti-gun violence proposal that would include strengthening background checks,” Murphy said.

Murphy said the president’s comments on the White House lawn this week suggest that he is backing away from a commitment to expanding background checks, but he still believes that common ground is possible.

“I think the chances of success here are less than 50-50, but I think it’s worth giving this a shot and I am looking forward to the process that I think will begin over the course of the next several days,” Murphy said.

Blumenthal said he is maintaining his push to encourage states to adopt their own Extreme Risk Protection Orders, also called red flag statues. He said Connecticut can be a model for states using their rights to enact gun law reform.

“There’s growing momentum for ERPO, and we’re looking at a grant and incentive program,” Blumenthal said.

He and Murphy agreed that the red flag statues are an easier political battle than expanding background checks, but they will continue to advocate for both policies. Murphy said the White House told him it is “interested in trying to find common ground on Sen. Blumenthal’s proposal.”

Blumenthal said he often speaks with Sen. Lindsey Graham, R-S.C., about strategies for passing the red flag laws they have co-sponsored in the Senate.

“My Republican colleagues need the backbone that only Donald Trump can provide,” he said.