President Biden is being urged by members of Congress to "leverage" the U.S. alliance with Qatar to help free the remaining hostages from the Oct. 7 attack, Axios has learned.

Why it matters: Qatar has played a key role in negotiations between Israel and Hamas, but has also been the subject of grassroots protests in the U.S. in recent weeks for its financial ties to Hamas.

What we're hearing: Rep. Josh Gottheimer (D-N.J.) is circulating a letter to Biden, a copy of which was obtained by Axios, arguing Qatar "has not fully leveraged its relationship with Hamas to ensure all hostages are released without delay."

• The letter points to the presence of senior Hamas leadership in Qatar and the country's financial support for Hamas as examples of its "significant leverage" over the militant group.
• "Please make clear to Qatar that it will be held accountable for every hostage not brought home. Qatar's failure to deliver on its commitments will harm bilateral relations," the letter says.
• The letter has garnered signatures from lawmakers in both parties and is expected to be sent to Biden on Wednesday.

Zoom in: Jewish groups have held a series of protests outside the Qatari embassy in recent days to call for the release of hostages in Gaza and criticize its ties to Hamas, according to Jewish Insider.

• Organizers of one of the protests accused Qatar of being a "terror supporting state" and called for it to "use its full weight and its leverage on Hamas and demand the immediate release of our hostages."
• The outlet reported that additional protests are planned in D.C., New York and Ottawa.
• Qatar's influence has been under the microscope before: After a Qatar-brokered ceasefire deal fell apart in December, Sens. Joni Ernst (R-Iowa) and Jacky Rosen (D-Nev.) urged Biden to push Qatar to bring Hamas back to the negotiating table.

Zoom out: The hundreds of millions of dollars in aid Qatar has given to Gaza were sent with the blessing of Israeli Prime Minister Benjamin Netanyahu, according to a CNN report in December.

Between the lines: "There is no question the U.S. needs to be pressuring Qatar ... frankly, pressuring Egypt, pressuring any of the other countries that can hold sway with Hamas," Rep. Kathy Manning (D-N.C.), the vice ranking member of the House Foreign Affairs Committee, told Axios.

• Manning said she has been told "negotiators have been working with Qatar, and that Qatar is being responsive," noting the country was "able to put together the first deal, and that deal worked pretty well."
• "Everybody wants as much pressure put on Hamas as possible, and Qatar seems to be the most likely entity that can put more pressure on Hamas," she added.

The other side: A Qatari official told Axios that the country's prime minister met with lawmakers and top Biden administration officials in Washington, D.C., this week and discussed Doha's efforts to mediate a deal and ways to foster the U.S.-Qatari bilateral relationship.

• The prime minister also met with the families of hostages, according to the official, who said "these meetings have taken place throughout the conflict and will continue until all the hostages are freed."
• "Letters and protests aimed at forwarding political agendas and fundraising are not helpful. Unlike the false allegations in the letter, Qatar neither controls nor funds Hamas, nor does it have control over Israel," the official said.
• The official stressed that Qatar's contribution in mediating talks has been "crucial and successful," saying they "worked diligently to secure the release of over 100 hostages" and remain "committed to continuing [these] important efforts."

What's next: The lawmakers' letter includes an apparent threat of sanctions on Qatar if the country doesn't step up its efforts to secure the release of hostages.

• "Congress is watching closely," it says. "If we do not see the release of more hostages, including all American citizens, in the days ahead, we will consider a menu of fast-track legislative options to hold Qatar accountable."

Editor's note: This story has been corrected to fix Sen. Jacky Rosen's name. It's also been updated with the Qatari official's comments.