Airstrikes on the Gaza Strip’s southernmost town of Rafah have killed at least 44 people as more than a million civilians sheltering in the area brace for the possibility of a full-scale Israeli ground offensive on the territory’s last place of relative safety.

As Israeli forces have expanded ground operations steadily southwards in their war against Hamas over the past four months, Rafah – situated on the border with Egypt, and home before the war to about 280,000 people – has become the last refuge for more than half of the strip’s population of 2.3 million.

Israel’s prime minister, Benjamin Netanyahu, said on Friday that he had instructed the Israel Defense Forces (IDF) and defence ministry to draw up plans for troops to enter Rafah and evacuate civilians, leading to widespread panic in the overcrowded makeshift tent camps that now cover the area.

With two-thirds of Gaza already under evacuation orders, widespread destruction throughout the coastal strip and continuing fighting, it is unclear to where such a large number of people could safely be moved.

The Egyptian foreign minister, Sameh Shoukry, said on Saturday that an Israeli ground offensive on Rafah would have “disastrous consequences,” and that Israel’s aim was eventually to force the Palestinians from their land.

An Egyptian official told the Guardian that under no circumstances would fleeing Palestinians be allowed to cross the border into the Sinai peninsula, and that any attempt to relocate them to Egyptian soil would collapse the peace deal between Egypt and Israel.

A doctor at a UN-run clinic in Rafah said: “I encountered an elderly woman who was looking for a wheelchair for her disabled husband. She said: ‘If I can’t get this chair for my husband, it will be our end. With the occupation in Gaza, how can I take him to Sinai? I cannot leave him alone in Gaza.’”

Israel has carried out airstrikes in Rafah almost daily, even after telling civilians in recent weeks to seek shelter there from fierce ground combat in Khan Younis, just to the north.

Three airstrikes on homes in the Rafah area killed 44 people overnight into Saturday, according to a health official and Associated Press journalists who saw the bodies arriving at hospitals. The strikes killed members of three families, including 12 children, the youngest three months old.

In Khan Younis, Israeli forces opened fire at Nasser hospital, the area’s largest, killing at least two people and wounding five, according to the medical charity Doctors Without Borders. Ahmed Maghrabi, a physician at the hospital, said in a Facebook post that Israeli tanks had reached the hospital gates on Saturday morning, trapping those inside and making the facility inaccessible to those in need of medical attention.

Israel’s threats of a full-scale attack on Rafah – designed to put pressure on the Hamas leadership, which is believed to be hiding in tunnels in the area – have not yet been realised, and Netanyahu did not provide details or a timeline in his announcement.

He has, however, implied the operation is inevitable, and appears ready to push ahead despite mounting warnings from aid agencies and the international community that a Rafah offensive would be a “bloodbath”.

“It is impossible to achieve the goal of the war of eliminating Hamas by leaving four Hamas battalions in Rafah,” Netanyahu’s office said on Friday.