GAZA - The Israeli army on Sunday expanded its ground operations in and around Gaza City, pushing tanks into residential neighborhoods under the cover of airstrikes and artillery fire, heightening fears of a full-scale invasion of the densely populated enclave.

Residents said Israeli armor rolled into the Zeitoun and al-Sabra districts south of Gaza City, and into Jabalia in the north, as warplanes pounded buildings and homes. Explosions and "fire belts" -- strips of land set ablaze by incendiary munitions -- were reported, forcing dozens of families to flee westward and southward in search of safety.

Mahmoud Basal, spokesman for Gaza's Civil Defense, said air and drone strikes hit homes, apartments, a school and tents for displaced people across the Strip. He said Israeli forces also opened fire on Palestinians gathering near two aid centers in central and southern Gaza. At least 25 people were killed and dozens wounded since dawn, he said.

Palestinian officials said high-rise buildings were hit in Zeitoun, Sabra and Jabalia, leaving many families trapped. Hospitals, already badly damaged and short of supplies, were struggling to cope. "The displaced do not know where to go. There are no safe areas left," Basal said.

The Hamas-run Gaza government media office condemned Israel's threats to invade Gaza City, home to more than 1 million people. It called the plan a "dangerous escalation" and warned an assault would amount to "a major war crime" given the collapse of the health system.

The Palestinian Foreign Ministry urged "decisive international action" to halt "Israel's deliberate policy" of famine. It said Gaza's hunger crisis was not caused by lack of resources but by blockade and bombardment, and vowed to press its case through diplomatic and legal channels.

The Israeli military said its forces had re-entered Jabalia to "further degrade Hamas' military capabilities," dismantling infrastructure above and below ground and preventing fighters from returning. "The troops' activity enables the expansion of combat into additional areas," it said in a statement.

Meanwhile, Hamas said it had agreed to a partial prisoner exchange and was ready for a full truce, but accused Israeli Prime Minister Benjamin Netanyahu of blocking a deal despite mediation by Egypt and Qatar. Hamas said only a ceasefire could secure the release of all Israeli hostages and held Netanyahu responsible for their fate.

Health authorities in Gaza said at least 10,842 Palestinians had been killed and 45,910 wounded since Israel stepped up its offensive on March 18. That brought the total death toll since the war began in October 2023 to 62,686, with 157,951 others injured. Officials said 289 people, including 115 children, had died from malnutrition or starvation, eight of them in the past 24 hours.