Israeli forces and Hamas fought fierce battles throughout Gaza yesterday, witnesses said, suggesting Israel's ground offensive was meeting stiffer resistance as the US nudged its ally to change a strategy that has inflicted a huge civilian death toll.

Residents in the small enclave reported fighting in Sheijaia, Sheikh Radwan, Zeitoun, Tuffah, and Beit Hanoun in north Gaza, east of Maghazi in central Gaza and in the centre and northern fringes of the main southern city of Khan Younis.

Hospitals in Deir al-Balah, Khan Younis and Rafah reported dozens of dead yesterday including two children. Four people were killed in an Israeli air strike on a house in Rafah and Israeli tanks were shelling targets just east of the city near the Egyptian border, medics and witnesses said.

The Israeli military yesterday said in an update that its forces had destroyed a Hamas command and control hub in Gaza City's heavily contested Sheijaia district and conducted a "targeted raid" on Hamas infrastructure in Khan Younis.

The heavy fighting, confirmed by many residents and Hamas sources reached by Reuters, raised questions about whether Israel's two-month-long aerial and ground blitz of Gaza had significantly weakened Hamas, which it has vowed to annihilate.

Unrelenting Israeli bombardment has laid much of Gaza to waste over the past two months, with nearly 19,000 people confirmed dead, according to Palestinian health officials, and thousands more feared buried under the rubble.

Tens of thousands of homeless Gazans who have crammed into Rafah at Gaza's southern end since December 3 are struggling in extremely overcrowded conditions, with the lack of latrines forcing many to defecate in the open, raising disease risks, the UN Humanitarian Office (OCHA) said in an update yesterday.

In many locations, solid waste was piling up without a safe means of disposal, and rats and insects were congregating in these areas, OCHA said.

Washington has been pressing Israel for weeks to do more to protect Gaza's civilians as a global outcry over a spreading humanitarian catastrophe, with medical care crippled and food, fuel and drinking water widely unavailable, has intensified.

US National Security Adviser Jake Sullivan had talks with Israel yesterday about shifting its military strategy in Gaza. Sullivan said after "very constructive talks" with Netanyahu that the war would transition to a new phase focused on precise targeting of Hamas leaders and on intelligence-driven operations.

Later in the day, he held talks with Palestinian President Mahmud Abbas at the latter's West Bank headquarters. Abbas told Sullivan that Gaza was an "integral part" of the Palestinian state, his office said, adding that "the president underscored that separation or any attempt to isolate any part of it is unacceptable".

Meanwhile, a projectile launched from Houthi-controlled Yemen struck the Liberia flagged, German-owned, Al Jasrah ship yesterday causing a fire but no injuries, a US defence official said.

In a second incident, maritime security company Ambrey reported that a Liberia-flagged container ship, MSC ALANYA, was ordered to alter course towards Yemen by people aboard a small craft assessed to be members of Yemen's Houthi movement.