Planes and tanks have pounded parts of Gaza City as Israel's plans to seize the territory's largest urban area increase pressure on nearly a million Palestinians living there.
Residents have spoken of uninterrupted explosions in northern and eastern parts of the city.
Israeli troops have also returned to blow up buildings in the refugee camp of Jabalia further north.
Sixty-four people were killed and nearly 300 injured in Israeli attacks in the past 24 hours, the territory's Hamas-run health ministry said.
It said the overall number of those killed since Israel launched its massive campaign to defeat Hamas had risen to 62,686 - with another 157,951 injured.
Israel's military launched an operation in Gaza in response to the Hamas-led attack on southern Israel on 7 October 2023, in which about 1,200 people were killed and 251 others were taken hostage.
Israel's Prime Minister Benjamin Netanyahu has vowed to defeat Hamas and defied international criticism over his plans to expand the war.
Some 60,000 reservists are being called up to take part in the Israeli operation.
While it has yet to begin in earnest, Israeli attacks on Gaza City have continued unabated - with the areas of Zeitoun and Shejayia hit from the air overnight into Sunday, as tank fire targeted Sabra neighbourhood.
The Israel Defence Forces (IDF) have also said that troops have returned to the Jabalia area in the past few days.
"The troops' activity enables the expansion of the fighting to additional areas and prevents Hamas terrorists from returning and operating in these areas," the IDF said.
Separately, the World Health Organization (WHO) announced on Sunday that a staff member had been released by the IDF after being held in Gaza since 21 July. There are no further details about the identity of the WHO worker or the reasons for his detention.
Netanyahu is also facing intense pressure in Israel - particularly from the families of hostages who want him to negotiate an end to the war in order to bring their captive relatives home.
Only 20 of 50 hostages still held in Gaza are believed to be alive.
The Israeli prime minister announced Israel's intention to conquer the entire Gaza Strip after indirect talks with Hamas on a ceasefire and hostage release deal broke down last month.
Mediators Qatar and Egypt are trying to secure a deal to avert the offensive and have presented a new proposal for a 60-day truce and the release of around half of the 50 hostages, which Hamas said it had accepted.
But Israeli officials have said they will no longer accept a partial deal and have demanded a comprehensive one that would see all the hostages released.
Israel's defence minister warned that Gaza City will be razed if Hamas does not agree to disarm and release all hostages.
The Israeli military has said it plans to evacuate Gaza City's entire population and move it to shelters in the south before troops move in.
Most of Gaza's population has been displaced many times.
The UN and non-governmental organisations have warned that an Israeli offensive in Gaza City will have a "horrific humanitarian impact".
More than 90% of homes are estimated to be damaged or destroyed, and the healthcare, water, sanitation and hygiene systems have collapsed.
Eighteen of Gaza's 36 hospitals are currently partially functional, according to the UN - 11 in Gaza City and its surrounding areas and one in a separate administrative district in North Gaza.
On Friday, conditions of famine were confirmed in Gaza City and its surrounding areas for the first time.
![[PHOTOS] Kindiki leads economic empowerment forum in Wajir](/_next/image?url=https%3A%2F%2Fcdn.radioafrica.digital%2Fimage%2F2025%2F08%2F5a14de4c-c863-48bb-819d-36f1f26ae789.jpeg&w=3840&q=100)
