Israel is facing growing international warnings over its planned offensive in Rafah – the city in southern Gaza crammed with Palestinian refugees.
UK Foreign Secretary David Cameron said “over half of Gaza’s population are sheltering in the area”, while Dutch FM Hanke Bruins Slot said there could be “many civilian casualties”.
Saudi Arabia warned of “very serious repercussions” if Rafah was stormed.
Gaza’s Hamas rulers said there could be “tens of thousands” of casualties.
On Sunday Hamas warned any operation would also undermine ongoing talks about a possible release of Israeli hostages held in Gaza.
Israel launched its operations in the Palestinian enclave after more than 1,200 people were killed in southern Israel on 7 October by Hamas gunmen, who also took about 240 people hostage.
On Sunday the Hamas-run health ministry in Gaza said 112 more Palestinians had been killed by the Israeli military over the previous day, bringing the overall death toll to more than 28,100 and more than 67,500 injured.
Many Gazans have ended up in Rafah having been forced to flee their homes elsewhere at least once.
Saturday’s warnings came a day after Israeli Prime Minister Benjamin Netanyahu ordered his military to prepare to evacuate civilians from the city ahead of an expanded offensive against Hamas.
“It is impossible to achieve the goal of the war without eliminating Hamas, and by leaving four Hamas battalions in Rafah. It is clear that intense activity in Rafah requires that civilians evacuate the areas of combat,” Mr Netanyahu’s office said.
The prime minister also rejected Hamas’s latest proposed ceasefire terms.
The US has already warned Israel that an invasion of Rafah as part of its assault on Gaza would be a “disaster”, while the EU and the UN both expressed their own concerns.
Aid groups say it is not possible to evacuate everyone from the city on the border with Egypt.
UN humanitarian co-ordinator Jamie McGoldrick, who has just been to Gaza to assess the situation, told the BBC’s Barbara Plett Usher that people in Rafah would have “nowhere to go” if Israeli troops launched their offensive.
“The safe areas that were declared are no longer safe. And if these people have to move – where can they move? We are really fearful of the horrific nature of where we are could only ever get worse,” he said.
Some 1.5 million Palestinians are believed to be in Rafah, seeking refuge from Israeli combat operations in the rest of the Gaza Strip. Most of them are living in tents.
In a social media post, Mr Cameron said he was “deeply concerned about the prospect of a military offensive in Rafah.
“The priority must be an immediate pause in the fighting to get aid in and hostages out, then progress towards a sustainable, permanent ceasefire.”
Meanwhile, Ms Bruins Slot described the situation in Rafah as “very worrying”.
“Many civilians in Gaza have fled south. Hard to see how large-scale military operations in such a densely populated area would not lead to many civilian casualties and a bigger humanitarian catastrophe. This is unjustifiable,” she added.
Also on Saturday, the Saudi foreign ministry issued a statement that warned against “targeting the city of Rafah in the Gaza Strip, which is the last resort for hundreds of thousands of civilians forced by the brutal Israeli aggression to flee”.
The ministry also repeated its “demand for an immediate ceasefire”.
