Israeli troops and tanks attacked Gaza's main northern city from both sides on Monday, three days after they began a major ground offensive in the Palestinian enclave that has drawn more international calls for civilians to be protected.

Israel's military said it had struck more than 600 militant targets over the past few days as it expanded ground operations in the Gaza Strip, where Palestinian civilians are in dire need of fuel, food and clean water as the war enters its fourth week.

The militants said they had repelled an attempted push from Israel tanks into Gaza City from the east and were fighting them on the border with Israel.

"Our duty today is fight and fight," the Islamic Jihad milliant group, fighting alongside Hamas, said in a statement, adding that now was not the time for a truce.

The Israeli military said it had killed four prominent Hamas operatives.

"IDF troops killed dozens of terrorists who barricaded themselves in buildings and tunnels, and attempted to attack the troops," it said.

Neither side commented on the other's reports.

Israel renewed warnings for civilians to move from the north of the tiny coastal enclave to the south as it began a big push into Gaza late on Friday to go after Hamas militants it says are hiding in a labyrinth of tunnels under Gaza City.

Many people have stayed in the city, afraid of becoming homeless like their forefathers and concerned by Israeli bombing further south.

On Monday, residents said Israeli forces carried out dozens of air strikes on the city's eastern side, with some reporting the roar of tanks rolling in amid exchanges of fire. A social media post appeared to show one tank on the main Salahudeen road that connects the city to the south.

Later, residents and the Hamas-run government's media office said the tanks had pulled back towards the fortified fence around Gaza. The militants' armed wing said intense mortar fire had pushed them back and fellow militants Islamic Jihad said its fighters were battling Israeli forces there.

To the west, the coast road was hit several times from the air and sea, residents said.

Reuters could not immediately verify the reports.

Palestinian health officials said air strikes had hit near three large hospitals in Gaza City on Monday. The U.N. humanitarian office OCHA said 117,000 civilians are sheltering alongside patients and doctors in hospitals in the north.

Israel has accused Hamas of placing command centres and weaponry near hospitals, which the group denies.

Air strikes could also be heard in the southern towns of Rafah near Gaza's only operational border crossing, with Egypt, as well as east of Khan Younis, where Palestinian media said Hamas clashed with Israeli troops.

Phone and internet cuts which blacked out Gaza on Friday had eased and OCHA said on Monday services were "largely restored", although telecoms providers said parts of the north were down.

CLASHES IN WEST BANK

Israel has said 1,400 people were killed when Hamas-led militants stormed through the south of the country on Oct. 7 and took 229 hostage. Hamas has released four so far and said 50 have been killed in retaliatory strikes.

Medical authorities in Hamas-run Gaza, which has a population of 2.3 million people, said on Monday that 8,306 people - including 3,457 minors - had been killed.

OCHA said rescuers were struggling to reach people.

"As of 29 October, about 1,800 people, including at least 940 children, have been reported missing and may be trapped or dead under the rubble, awaiting rescue or recovery," it said.

The U.N. agency also said that armed groups continued firing rockets at Israel indiscriminately, with no fatalities reported.

The Israeli defence ministry issued video footage of what it said were manoeuvres inside Gaza showing soldiers in buildings, tanks on a main road, and air strikes on what it said were buildings occupied by Hamas.

Reuters was not able to independently verify the timing or location of the video and Israel's military said it would not reveal where it was filmed.

"We are moving from the ground, spotting the terrorists and attacking from the air. There is also direct engagement between ground forces and terrorists. The fighting is taking place inside the Gaza Strip," military spokesperson Rear Admiral Daniel Hagari said.

Hamas and Islamic Jihad said they were also fighting Israeli forces in the Israeli-occupied West Bank city of Jenin. The Palestinian health ministry said four people were killed there on Monday and Israel said an air strike killed several fighters.

Israel said it had arrested 700 Hamas militants in the West Bank. The Palestinian health ministry said 121 people had been killed in the West Bank and East Jerusalem since Oct. 7. The Palestinian Prisoners Association said 1,680 people had been detained, including women, the elderly and minors.

AIRPORT UNREST IN RUSSIA

The conflict has lead to large demonstrations worldwide in support of the Palestinians, and antisemitic and Islamophobic harassment and attacks are increasing.

Russian authorities said they had taken over an airport in the predominantly Muslim Dagestan region and arrested 60 people after hundreds of anti-Israel protesters stormed the facility in search of the Jewish passengers from a plane from Israel.

Officials said 20 people in the airport were wounded before security forces contained the unrest on Sunday. The plane's passengers were safe, security forces told Reuters.

Israel's widening ground attacks on Gaza have spurred international calls for a "humanitarian pause" to allow aid in.

Hamas wants a five-day pause in Israel's operations to allow aid and fuel into Gaza in return for the release of all civilian hostages held by the militants, a source briefed on Qatar-mediated negotiations between Israel and Hamas told Reuters.

OCHA said 33 trucks carrying water, food and medical supplies had entered Gaza on Sunday, the biggest delivery so far, but many more were required to meet urgent needs and prevent civil unrest. People stormed aid stores on Sunday in search of food.