The U.S. is working on a deal between Israel and Hamas for a pause in fighting in Gaza for at least six weeks to allow the release of additional hostages still held captive by Hamas, President Joe Biden said Monday.

After a "sustained period of calm" in Gaza, "we could then take the time to build something more enduring," Biden said after a meeting at the White House with Jordanian King Abdullah II.

Biden said he has spoken to Israeli Prime Minister Benjamin Netanyahu, as well as leaders of Qatar and Egypt, "to push this forward."

"The key elements of the deal are on the table," Biden said. "There are gaps that remain but I've encouraged Israeli leaders to keep working to achieve the deal. The United States will do everything possible to make it happen."

Israel has said about 100 hostages remain alive in Hamas captivity in Gaza out of about 240 who were taken by Hamas during the militant group's violent Oct. 7 attack on Israel. About 100 were released during a previous cease-fire in November, and militants are believed to be holding the remains of more than 30 others, most of whom died in the Oct. 7 attacks.

Biden, who has faced a growing backlash on the left for his unwavering support for Israel, sharpened his critique of Israel again Monday after last week saying Israel's military response in Gaza has been "over the top."

"Too many of the over 27,000 Palestinians killed in this conflict have been innocent civilians including thousands of children," Biden said. "And hundreds of thousands have no access to food, water and other basic services. Many families have lost not just one, but many relatives, and cannot mourn for them, even bury them, because it's not safe to do so."

Biden added: "Every innocent life lost in Gaza is a tragedy. Just as every innocent life lost in Israel is a tragedy as well. We pray for those lives taken, both Israeli and Palestinians."

Israeli security forces stormed an apartment in the heart of Rafah in southern Gaza on Monday, freeing two hostages and killing their three guards in a daring operation that Gaza officials say claimed the lives of scores of Palestinians.

Biden said he discussed Israel's impending invasion of Gaza with King Abdullah II and reaffirmed that Israel "should not proceed without a credible plan for ensuring the safety and support of more than 1 million people sheltering there."

King Abdullah II, with Biden standing behind him, said "we cannot afford an Israeli attack on Rafah."

"It is certain to produce another humanitarian catastrophe," the king said. "We cannot stand by and let this continue. We need a lasting ceasefire now. This war must end."