Israeli forces pounded besieged Gaza on Wednesday and fought Hamas around several hospitals, despite a UN Security Council demand for a ceasefire.

Talks in Qatar towards a truce and hostage release deal involving US and Egyptian mediators have brought no result so far, with Israel and the Palestinian militant group blaming each other.

Tensions have risen between Israel and its top ally the United States over dire food shortages in Gaza and the soaring civilian death toll in the war sparked by Hamas's attack on October 7.

The US also opposes Israeli plans to push its ground offensive into the far-southern city of Rafah, crowded with up to 1.5 million people, most of them displaced by the war.

In heavy overnight bombardment, Israeli strikes again hit Gaza City and Rafah, where a fireball lit up the sky.

Israeli forces have battled militants in and around three Gaza hospitals, raising fears for patients, medical staff and displaced people inside them.

Fighting has raged since last week around Gaza City's Al-Shifa Hospital, the territory's largest, and more recently near two hospitals in the main southern city of Khan Yunis, Al-Amal and Nasser.

The army and Shin Bet security service said they were "continuing to conduct precise operational activities" in both cities "while preventing harm to civilians, patients, medical teams and medical equipment".

The army said dozens of militants have been killed "in the area" of Al-Shifa and "hundreds of terrorists have been apprehended".

Israeli tanks and armoured vehicles have also massed around the Nasser Hospital, the Gaza health ministry said, adding that shots were fired but no raid had yet been launched.

A military spokesperson told AFP: "We're operating in the area, but we haven't been inside the hospital."

The Palestinian Red Crescent warned that thousands were trapped inside and "their lives are in danger".