RIYADH (Reuters) - Palestinian President Mahmoud Abbas said on Sunday only the United States could stop Israel 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.

Israel, which has threatened for weeks to launch an all-out assault on the neighbourhood saying its goal is to destroy Hamas' remaining battalions there, stepped up airstrikes on Rafah last week.

Western countries, including Israel's closest ally the United States, 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.

"What will happen in the coming few days is what Israel will do with attacking Rafah because all the Palestinians from Gaza are gathered there," Abbas said, adding that only a "small strike" on Rafah would force the Palestinian population to flee the Gaza strip.

"The biggest catastrophe in the Palestinian people's history would then happen."

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 West Bank and into Jordan.

Israel launched its offensive in Gaza after Hamas led an attack on southern Israel on Oct. 7 in which Israel said 1,200 people were killed and 253 taken hostage.

More than 34,000 Palestinians have since been killed, according to the Gaza health ministry, and most of the population displaced.