Palestinians in Gaza reported fierce air and artillery strikes early on Monday as Israeli troops backed by tanks pressed into the enclave with a ground assault that prompted more international calls for civilians to be protected.

Israel’s military said it had struck over 600 militant targets over the past few days as it continued to expand ground operations in the Gaza Strip, where Palestinian civilians are in dire need of fuel, food and clean water as the conflict enters its fourth week.

“IDF troops killed dozens of terrorists who barricaded themselves in buildings and tunnels, and attempted to attack the troops,” the military said in a statement.

Israeli air strikes hit areas near Gaza’s Al-Shifa and Al-Quds hospitals, and Palestinian militants clashed with Israeli forces in a border area east of the city of Khan Younis in the south, Palestinian media said.

Medical officials in Gaza said at least 20 Palestinians had been killed and dozens wounded overnight as Israeli ground forces pushed into the coastal enclave from multiple directions.

Residents said they could hear shooting and explosions all night. Islamist groups Hamas and Islamic Jihad said their members were engaged in fighting with Israeli forces in Gaza as well as the West Bank city of Jenin.

Reuters was not able to independently confirm the reports.

Israel released images of battle tanks on the west coast of the enclave, signalling a potential effort to surround Gaza’s main city two days after the Israeli government ordered expanded ground incursions. Some pictures posted online also appeared to show Israeli soldiers waving an Israeli flag deep inside Gaza. Reuters could not verify the images.

Israel’s self-declared “second phase” of a three-week war against Iranian-backed Hamas militants has been largely kept from public view, with forces moving under darkness and a telecommunications blackout cutting off Palestinians.

The phone and internet cuts appeared to ease on Sunday, but telecoms provider Paltel said Israeli air strikes had again knocked out internet and phone service in parts of Gaza’s northern sections, where Hamas has command centres.

The outages have severely hampered rescue operations for casualties of the Israeli barrages.

The reported strikes near hospitals came after the Palestinian Red Crescent said on Sunday it had received warnings from Israeli authorities to immediately evacuate Al-Quds hospital, where some 14,000 people have sought shelter.

Israel has accused Hamas of locating command centres and other military infrastructure in Gaza hospitals, which the group denies.

Palestinian officials said about 50,000 people had also taken shelter in Al-Shifa Hospital, adding that they were concerned about Israeli threats to the facility.

Israel has tightened its blockade and bombardment of Gaza since Hamas gunmen stormed into Israel on Oct. 7. Israeli authorities say the militants killed some 1,400 people and took at least 239 hostages.

The military has also stepped up operations against Islamist groups in the West Bank, killing scores of Palestinians and arresting hundreds.

Israeli security forces killed four people during a raid in the occupied West Bank city of Jenin early on Monday, the Palestinian health ministry said.

Calls for a pause

The stepped-up attacks coincided with a mounting international outcry for a “humanitarian pause” to allow aid in.

Qatar-mediated negotiations between Israel and Hamas continued on Sunday, a source briefed on the talks told Reuters, and included discussions about the possible release of hostages.

Hamas wants a five-day humanitarian pause in Israel’s operations to allow aid and fuel into the besieged Gaza Strip in return for the release of all civilian hostages held by the militants, said the source, speaking on condition of anonymity.

More than half the hostages held by Hamas have foreign passports from 25 countries, including 54 Thai nationals, according to the Israeli government.

On Monday, the United Nations Security Council is due to be briefed on the humanitarian situation in Gaza. The 15-member body has unsuccessfully voted four times in the past two weeks on draft resolutions that aimed to take action on the war, but the 193-member U.N. General Assembly voted overwhelmingly on Friday to call for an immediate humanitarian truce.

US President Joe Biden pressed Israeli Prime Minister Benjamin Netanyahu in a call on Sunday to protect civilians in Gaza and “immediately and significantly increase the flow of humanitarian aid”, the White House said.

Colonel Elad Goren of COGAT, the Israeli defence ministry agency that co-ordinates with the Palestinians, said Israel will allow a dramatic increase in aid to Gaza in the next few days and Palestinian civilians should head to a “humanitarian zone” in the south of the tiny territory.

Medical authorities in Gaza, which has a population of 2.3 million people, said on Sunday 8,005 people - including 3,324 minors - had been killed.

The Hamas-run Gaza government’s media office said 116 medics and 35 journalists have been killed since the conflict erupted.

Reuters was unable to independently verify these figures

Israel has vowed to annihilate Hamas, a task it described as necessitating protracted ground assaults in, around and under Gaza City, where the militants have an extensive subterranean bunker network.

There are fears too that the war will spill over into the region, including in Lebanon, where the Israeli army and Iranian-backed Hezbollah group have been exchanging fire.

On Monday, Syrian state TV said Israeli air strikes targeted two army posts in Daraa, leading to “some material losses”.

The conflict has spurred large demonstrations worldwide in support of the Palestinians. On Sunday several thousand people rallied in Beirut to show solidarity with Gaza.

Russian authorities said police had taken over an airport in the predominantly Muslim Dagestan region and arrested 60 people after hundreds of anti-Israel protesters stormed the facility on Sunday when a plane from Israel arrived.