Jordan's King Abdullah II appealed for a full ceasefire to end the war in Gaza after talks with Joe Biden, striking a discordant note with the US president who is seeking a shorter six-week pause to allow Israel time to defeat Hamas.
Speaking at the White House with Abdullah by his side, Biden said civilians in the southern city of Rafah must be protected as Israel considers a ground incursion, while the Jordanian warned against any offensive at all.
Biden, 81, said that the United States was working to negotiate a pause in fighting of least six weeks in the Gaza strip as part of a wider deal that would also involve the release of hostages.
"We need a lasting ceasefire now. This war must end," said the Jordanian monarch, who has repeatedly pushed for a full truce to end the conflict that started when Hamas attacked Israel on October 7.
In his first face-to-face meeting with Biden since the attack, Abdullah said the world "cannot afford an Israeli attack" on Rafah.
"It is certain to produce another humanitarian catastrophe. We cannot stand by and let this continue."
The United States has consistently refused to call for a full ceasefire, saying that it backs Israel's drive to defeat Hamas, and calling for shorter pauses with hostage deals instead.
However Biden has also started to take a harder line with key US ally Israel, saying last week that said Israel's response in the Gaza Strip had been "over the top."
Flanked by US and Jordanian flags, Biden and the king had earlier embraced as they met on the front steps of the White House for their first face-to-face talks since the October 7 attacks.
They were accompanied by First Lady Jill Biden, Queen Rania and Jordanian Crown Prince Hussein.
Biden joked during the arrival ceremony that "everybody does" when asked if Benjamin Netanyahu was following his advice on avoiding an offensive in Rafah.
But he later said he had insisted that civilians in Rafah, where more than one million Palestinians are trapped, "need to be protected."
He said Washington was working on a hostage deal between Israel and Hamas that would bring (an) immediate and sustained period of calm to Gaza for at least six weeks."
The two leaders also discussed efforts to ensure that the conflict does not spread across a volatile region.
Three US troops were killed in a drone attack on a base in Jordan in January, triggering American airstrikes against Iranian-backed militant groups in Iraq and Syria.
Washington is the first stop of a tour by the Jordanian king that will also take in Canada, France and Germany, amid mounting international efforts for a deal to pause fighting in Gaza and free hostages held there by Hamas.
The bloodiest ever Gaza war broke out after Hamas launched an unprecedented attack on southern Israel that resulted in the deaths of about 1,160 people, mostly civilians, according to an AFP tally based on official Israeli figures.
Israel has responded with a relentless bombardment and ground offensive in Gaza that the Palestinian territory's Hamas-run health ministry says has killed at least 28,340 people, mostly women and children.
Biden was meant to travel to Jordan for talks with Abdullah when he visited Israel less than two weeks after the initial attack, but the meeting was canceled after an explosion at a Gaza hospital caused anger across the Arab world.
US Secretary of State Antony Blinken met Abdullah in Amman in January. The Jordanian monarch urged the top diplomat to push for a ceasefire in Gaza and end the humanitarian crisis there.
