By Nidal al-Mughrabi and Maytaal Angel
GAZA/JERUSALEM Thousands of Palestinian civilians trudged in a forlorn procession out of the north of Gaza on Wednesday seeking refuge from Israeli air strikes and fierce ground fighting between Israeli troops and Hamas militants.
The exodus took place in a four-hour window of opportunity announced by Israel, which has told residents to evacuate the north encircled by its armoured forces or risk being trapped in the violence.
But the central and southern parts of the small, besieged Palestinian enclave also came under fire again as the war between its Islamist Hamas rulers and Israel entered its second month.
Palestinian health officials said an air strike that hit houses in the Nusseirat refugee camp killed 18 people on Wednesday morning. In Khan Younis, six people, including a young girl, were killed in an air strike.
"We were sitting in peace when all of a sudden an F16 air strike landed on a house and blew it up, the entire block, three houses next to each other," said a witness, Mohammed Abu Daqa.
"Civilians, all of them civilians. An old woman, an old man and there are others still missing under the rubble."
Gaza City, the Hamas militant group's main bastion in the territory, is now surrounded by Israeli forces. The military said troops have advanced to the heart of the city, while Hamas says its fighters have inflicted heavy losses.
TUNNEL NETWORK
Chief Israeli military spokesperson Rear Admiral Daniel Hagari said combat engineers were using explosive devices to destroy a Hamas tunnel network that stretches for hundreds of kilometres (miles) beneath Gaza.
In a statement on Wednesday, the military said it had destroyed 130 tunnel shafts so far. "Combat engineers fighting in Gaza are destroying the enemy's weapons and are locating, exposing and detonating tunnel shafts," it said.
Air strikes had also killed a Hamas weapons maker, Mahsein Abu Zina, and several fighters, the Israeli military said.
Israeli tanks have met heavy resistance from Hamas fighters using the tunnels to stage ambushes, according to sources with the Iran-backed Hamas and separate Islamic Jihad militant groups. Israel says 33 of its soldiers have been killed.
U.N. officials and G7 world powers stepped up appeals for a humanitarian pause in the war to help alleviate the suffering of civilians in Gaza, where whole neighbourhoods have been razed by Israeli bombardment and basic supplies are running out.
"It is ... important to make Israel understand that it is against (its) interests to see every day the terrible image of the dramatic humanitarian needs of the Palestinian people," U.N. Secretary General Antonio Guterres told a Reuters NEXT conference on Wednesday. "That doesn't help Israel in relation to the global public opinion."
Palestinian officials said 10,569 people have now been killed, 40% of them children. The level of death and suffering is "hard to fathom", U.N. health agency spokesperson Christian Lindmeier said in Geneva.
Israel struck at Gaza in response to a cross-border Hamas raid on southern Israel on Oct. 7 in which gunmen killed 1,400 people, mostly civilians, and took about 240 hostages, according to Israeli tallies.
Israel says it will not agree to a ceasefire before the hostages are released. Hamas says it will not stop fighting while Gaza, one of the world's most densely populated places, is under attack.
FLEEING THE BOMBS
Thousands of Palestinians fleeing from the north wearily made their way in a long line past wrecked and bomb-scarred buildings, witnesses said.
The Israeli military had told them they should move south of the Wadi Gaza wetlands along the main Salah al-Din Road. Huge numbers of displaced people from among Gaza's 2.3 million population are already crammed into schools, hospitals and other sites in the south.
Thousands of others remain inside the encircled north, including at Gaza City's main Al Shifa hospital, where Um Haitham Hejela was sheltering with her young children in an improvised tent.
"The situation is getting worse day after day," she said. "There is no food, no water. When my son goes to pick up water, he queues for three or four hours in the line. They struck bakeries, we don't have bread."
Israel's stated intention is to wipe out Hamas, pounding Gaza from air, land and sea while ground troops have moved in to cleave the narrow coastal strip in two in fierce urban fighting amid the ruins of buildings.
Palestinian media reported clashes between militants and Israeli forces near al-Shati (Beach) refugee camp in Gaza City. Hamas's armed wing, the Izz ad-Din al-Qassam Brigades, said its fighters had destroyed an Israeli tank in Gaza City.
Reuters was unable to verify the battlefield claims of either side.
There was no further word from Israel on the possible fate of Yahya Sinwar, the most senior Hamas leader in Gaza and believed to be a key planner of the Oct. 7 attacks. Israel said on Tuesday he had been cornered in his bunker.
ISRAELI PRESENCE 'NOT UNLIMITED OR FOREVER'
Israel has so far been vague about its long-term plans if it achieves its stated objective of vanquishing Hamas.
A senior Israeli official, speaking on condition of anonymity, told reporters in Washington late on Tuesday that Israel has no intention of reoccupying the Gaza Strip or controlling it for "a long time".
"We assess that our current operations are effective and successful, and we'll continue to push," the official said. "It's not unlimited or forever."
Israeli Prime Minister Benjamin Netanyahu told ABC news earlier this week Israel would seek to have security responsibility for Gaza "for an indefinite period", prompting U.S. officials to caution against an Israeli "reoccupation".
(Reporting by Nidal al-Mughrabi in Gaza, Maytaal Angel, Emily Rose and Maayan Lubell in Jerusalem, Rami Amichay in Tel Aviv and Matt Spetalnick in Washington; writing by Michael Perry, Angus MacSwan and Mark Heinrich; Editing by Simon Cameron-Moore, Peter Graff and Alex Richardson)