Amid growing international concern over the plight of civilians, Israeli tanks shelled the eastern sector of Rafah city overnight, residents said, although the anticipated ground offensive did not appear to have started.
The Israeli military said its forces killed dozens of Palestinian fighters in clashes in the southern and central Gaza Strip over the last 24 hours, including 30 in Khan Younis, a city close to Rafah on the coastal enclave's border with Egypt.
Gaza health officials said an Israeli strike on a house in Nusseirat refugee camp in central Gaza killed 16 Palestinians overnight.
In Khan Younis, Israeli tanks advanced further from the west and the east as bombing continued, residents said.
Israeli forces ordered displaced people in some shelters to head to Rafah. But the boom of tank shelling east of Rafah caused waves of panic inside the makeshift tent camps housing the displaced.
With the war between Israel and Hamas militants now in its fifth month, attention is focused on the situation in Rafah. Around half of Gaza's 2.3 million people are now living there in desperate conditions, including many who fled other areas pulverized by Israel's offensive.
Israel says it intends to wipe out the Hamas fighters operating in Rafah and that it will evacuate civilians. Aid officials and foreign governments say there is nowhere for them to go, and Egypt has made clear it will not allow a refugee exodus over its border.
Much of the densely populated enclave is in ruins, with 28,473 Palestinians killed and 68,146 wounded since October 7, according to Gaza health officials who announced 133 new Palestinian deaths in the past 24 hours.
Many other people are believed to be buried under rubble. Supplies of food, water and other essentials are running out and diseases are spreading.
"Since Israel said they are invading Rafah soon...we read our last prayers every night. Every night we say farewell to one another and to relatives outside Rafah," said 30-year-old Aya, who is living in a tent with her mother, grandmother and five siblings.
"Unless the world show some mercy and stop Israel from raiding Rafah, we think we are not going to survive. The sounds of shelling and explosions get closer and closer," she said via a chat app.
On Monday, U.S. President Joe Biden and Jordan's King Abdullah kept up pressure for a cease-fire.
"The United States is working on a hostage deal between Israel and Hamas which would bring an immediate and sustained period of calm into Gaza for at least six weeks," Biden told reporters in Washington.
The hostages were seized in the October 7 raid on southern Israel by Hamas militants which killed 1,200 people and triggered Israel's military offensive. Securing their return is a priority for Prime Minister Benjamin Netanyahu's government as it aims also to eradicate Hamas, which rules Gaza.
Abdullah underscored the urgency of the plight of the Palestinians, especially those trapped in Rafah.
"We cannot stand by and let this continue," he said. "We need a lasting ceasefire now. This war must end."
In Cairo, senior officials from the U.S., Egypt, Israel and Qatar were scheduled to meet to work on a three-phase framework that would see the release of hostages and achieve an extended pause, sources familiar with the matter said.
Biden has shown increasing exasperation with Netanyahu for not heeding his appeals to do more to minimize casualties and protect civilians in Gaza. He has urged Israel not to undertake a ground offensive in Rafah without a plan to protect the Palestinian civilians who are massed there.
The U.S. is Israel's closest ally and biggest foreign arms provider, giving $3.8 billion in military aid annually, and there was no indication that Washington would hold up such aid. The U.S. State Department said cutting aid would not be "more impactful than the steps Washington has already taken."
Netanyahu last week ordered Israel's military to create a plan to evacuate civilians during any ground offensive. Asked about those plans, an Israeli military spokesperson on Monday said he still did not know how it would be done.
The United Nations on Monday intensified calls for a cease-fire and opposed the idea of moving civilians in Rafah.
U.N. spokesman Stephane Dujarric told reporters, "We will not be party to forced displacement of people. As it is, there is no place that is currently safe in Gaza."
"You can't send people back to areas littered with unexploded ordnance, not to mention a lack of shelter," Dujarric said.
European Union foreign policy chief Josep Borrell on Monday suggested that the way to educe civilian casualties would to be stop arms supplies to Israel.