More than a million Palestinians are sheltering in the southern Gaza city after being displaced by Israeli attacks.

Palestinian Authority President Mahmoud Abbas says only the United States could stop Israel from attacking the border city of Rafah in Gaza, adding that the assault, which he expects within days, could force much of the Palestinian population to flee the enclave.

“We call on the United States of America to ask Israel to not carry on the Rafah attack. America is the only country able to prevent Israel from committing this crime,” Abbas told a special meeting of the World Economic Forum in the Saudi capital Riyadh on Sunday.

Israel, which has threatened for weeks to launch an all-out assault on the city, saying its goal is to destroy Hamas’s remaining battalions there, stepped up air attacks on Rafah last week.

Western countries, including Israel’s closest ally the US, have pleaded with it to hold back from attacking the southern city, which abuts the Egyptian border and is sheltering more than a million Palestinians who fled Israel’s seven-month-long assault on much of the rest of Gaza.

Abbas said that even a “small strike” on Rafah would force the Palestinian population to flee Gaza.

“The biggest catastrophe in the Palestinian people’s history would then happen,” he said.

Abbas reiterated that he rejects the displacement of Palestinians into Jordan and Egypt and said he is concerned that once Israel completes its operations in Gaza, it will then attempt to force the Palestinian population out of the occupied West Bank and into Jordan.

Al Jazeera’s Zein Basravi, reporting from Ramallah, said that Abbas’s remarks were significant as it was the first time a senior leader in the PA made such a statement, but added that the Palestinians expect more from the leader of the PA.

“Abbas is simply echoing the things that the Palestinians we have been speaking to said for the last six months,” he said.

“The reaction to Abbas’s remarks on the Palestinian streets is likely to mirror a broader political response. The people we have been speaking to say that what they see is a speech from their leader, far too late and far too weak.”

Israel launched its offensive in Gaza after Hamas led an attack on southern Israel on October 7 in which Israel said 1,139 people were killed and 253 taken captive.

More than 34,400 Palestinians have since been killed, according to the Gaza health ministry, and most of the population is displaced.

Hundreds of thousands of people sheltering in Rafah have nowhere to flee in the face of Israel’s offensive that has levelled large swaths of the urban landscape in the rest of the territory.

United Nations officials and human rights groups warn that an attack on Rafah will be catastrophic.