The leaders of France, Egypt and Jordan have warned Israel against a threatened offensive in the southern Gaza city of Rafah, urging an "immediate" ceasefire in its war on Hamas.

"We warn against the dangerous consequences of an Israeli offensive on Rafah, where more than 1.5 million Palestinian civilians have sought refuge," they said in a joint editorial published in several newspapers.

"Such an offensive will only bring more death and suffering, heighten the risks and consequences of mass forcible displacement of the people of Gaza and threaten regional escalation."

The editorial was signed by France's President Emmanuel Macron, Egypt's President Abdel Fattah al-Sisi and Jordan's King Abdullah II.

The United States said earlier it opposes any assault on Rafah, after Israel's Prime Minister Benjamin Netanyahu said a date for an attack had been set.

The three leaders urged that a U.N. Security Council resolution calling for an "immediate ceasefire... be fully implemented without further delay" and that all hostages held by Hamas be released, also in line with the council's demands.

"The war in Gaza and the catastrophic humanitarian suffering it is causing must end now," the three leaders said in the op-ed published by Le Monde in France, the Washington Post in the United States, Al Rai in Jordan and Al Ahram in Egypt.

They called for a "massive increase" in aid being allowed into Gaza.

Israel is under growing international pressure to agree to a ceasefire, including from its top ally and arms supplier the United States.

Hamas meanwhile said on Monday it was studying a proposal for a truce and hostage-prisoner swap after talks in Cairo.

Israel's Defence Minister Yoav Gallant said it was the right time for a deal, six months into a war with the Islamist militants in Gaza.

But while negotiations continued, Netanyahu said a date has been set for sending troops into Rafah.

The U.S. State Department reiterated that an invasion would have "an enormously harmful effect" on civilians, and ultimately Israeli security.

The war began with the October 7 attack against Israel by Hamas militants that resulted in the deaths of 1,170 people, mostly civilians, Israeli figures show.

Palestinian militants also took more than 250 Israeli and foreign hostages, 129 of whom remain in Gaza, including 34 the army says are dead.

Vowing to destroy Hamas, Israel launched a retaliatory offensive that has killed at least 33,207 people in Gaza, mostly women and children, according to Hamas-run Gaza's health ministry.