Hamas chief Ismail Haniyeh has blamed Israel for a lack of progress in achieving a ceasefire deal in Gaza, the group has said in a statement.

Haniyeh said on Saturday the Palestinian group would not accept anything less than a complete cessation of hostilities, Israeli withdrawal from Gaza, and “lifting of the unjust siege”.

“It is clear so far that the occupation [Israel] continues to manoeuvre and procrastinate on the files of interest to our people, while its position revolves around the release of prisoners held by the resistance,” Haniyeh said.

He added that Israel must also free Palestinian prisoners serving long sentences in any upcoming swap deal.

Meanwhile, Israeli forces carried out arrests in Nasser Hospital, Gaza’s largest functioning medical facility, health officials and the military said on Saturday, as air raids hit across the enclave.

“Occupation forces detained a large number of medical staff members inside Nasser Medical Complex, which they [Israel] turned into a military base,” said Gaza Health Ministry spokesperson Ashraf al-Qudra.

Following Israel’s incursion into Nasser Hospital in Khan Younis, which began on Thursday, at least five patients died after electricity was severed and oxygen supplies cut, Gaza’s Ministry of Health announced on Friday.

The Israeli military said it was hunting for fighters in Nasser and had so far arrested 100 suspects on the premises, killed fighters near the hospital and found weapons inside it.

Hamas has denied allegations that its fighters use medical facilities for cover. At least two released Israeli hostages have said they were held in Nasser, but Israel has failed to provide overwhelming evidence to back up previous accusations that hospitals have been used as Hamas command centres, or that captives have been held in hospitals.

Israel’s repeated attacks on hospitals have been described by human rights groups as “unlawful” with Human Rights Watch calling for them to be “investigated as war crimes”, and South Africa alleging at the International Court of Justice (ICJ) in The Hague that attacks on Gaza’s healthcare system were evidence of “genocidal acts” committed by Israel.

The Israeli incursion into the hospital has raised alarm about patients, medical workers and displaced Palestinians sheltering there.

About 10,000 people were seeking shelter at the hospital earlier this week, but many left either in anticipation of the Israeli raid or because of Israeli orders to evacuate, the Gaza Health Ministry said.

Israeli air raids hit central Gaza

Across the Gaza Strip, at least 83 people were killed in Israeli air raids since Friday, health officials said, including one person on Saturday in Rafah, an area that borders Egypt and which Israel now claims is Hamas’s last bastion.

The Palestinian Wafa news agency reported on Saturday that Israeli air raids killed at least eight Palestinian civilians including children and injured dozens more when their residential homes were bombed in Zawaida in central Gaza, according to local and medical sources.

A series of air raids hit Deir el-Balah in central Gaza, an area where displaced Palestinians are returning to since Israel intensified attacks on the southern city of Rafah.

Raids hit the east of the city, an area that has come under heavy bombardment over the past week, as well as the south. Ambulances were rushed to the scene to take casualties to the hospital.

“That was insane,” Hany Allouh, a 39-year-old father of two young children. “The rockets flew above us and caused an enormous explosion. They exploded one after the other, causing panic among the people in the streets.”

The Israeli military said its jets had killed numerous fighters in Gaza since Friday.

Across the border, air raid sirens warning of incoming rockets sounded in the southern Israeli city of Ashkelon on Saturday.

‘Catastrophic’ consequences

In the face of widespread international condemnation, Israel has insisted it will soon launch a ground invasion of Rafah. It is where an estimated 1.4 million of the enclave’s 2.3 million population has been forcibly displaced in Israeli attacks across Gaza in the four-month conflict.

Six humanitarian and human rights organisations have warned of the “catastrophic” consequences of an Israeli ground offensive in Rafah.

The joint statement was signed by the heads of Oxfam, Amnesty International, ActionAid, War Child, the Danish Refugee Council and Handicap International.

“If Israel launches its proposed ground offensive, thousands more civilians will be killed and the current trickle of humanitarian aid risks coming to a complete halt. If this military plan is not stopped immediately, the consequences will be catastrophic,” the statement said.

European Union’s foreign policy chief Josep Borrell also renewed calls for Israel to avoid taking military action in Rafah.

Such action would “worsen an already catastrophic humanitarian situation,” Borrell wrote on X.

On Friday, US President Joe Biden said he repeatedly told Israeli Prime Minister Benjamin Netanyahu there “has to be a temporary ceasefire” in Gaza during “extensive” conversations this week.

Biden said he cautioned Netanyahu against moving forward with a military operation into Rafah without a “credible and executable plan” to protect Palestinians sheltering there.

Reporting from Washington, DC, Al Jazeera’s Kimberly Halkett said it was “unclear” if Netanyahu was listening to Biden.

“Historically, he has not, especially when it comes to the US cautioning about how to conduct the Israeli military campaign,” Halkett said.