At least 1,900 Palestinians have been killed in the blockaded enclave of Gaza in a brutal air campaign of reprisal attacks by Israel as infantry forces from the IDF made their first raids into the Gaza Strip.

Israeli military spokesperson Rear Admiral Daniel Hagari claimed troops backed by tanks had mounted raids to attack Palestinian rocket crews and seek information on the location of hostages, the first official account of ground troops in Gaza since the crisis began.

Prime Minister Benjamin Netanyahu said a campaign of retaliation had ‘only just begun’. Israel has vowed to annihilate Hamas after its fighters burst out of Gaza a week ago and carried out operation in southern Israel.

Since then Israel has placed the Hamas-run Gaza Strip, home to 2.3 million Palestinians, under a total siege and bombarded it with unprecedented air strikes.

On Friday, more than a million residents of northern Gaza received a notice from Israel to flee south within 24 hours, a deadline that expired at 5 a.m. (0200 GMT). Hamas vowed to fight to the last drop of blood and told residents not to go.

“We have seen a significant movement of Palestinian civilians towards the south,” Israeli military spokesperson Lieutenant Colonel Jonathan Conricus told a video briefing early on Saturday.

“Around the Gaza Strip, Israeli reserve soldiers in formation (are) getting ready for the next stage of operations,” he added.

“They are all around the Gaza Strip, in the south, in the centre and in the north, and they are preparing themselves for whatever target they get, whatever task.

Several thousand Gaza residents took to roads heading out of the northern part of the Gaza Strip, but it was impossible to assess their numbers. Gaza authorities said 70 people were killed and 200 were wounded when Israel struck cars and trucks carrying people fleeing the north of the strip for the south.

Many others said they would not leave.

“Death is better than leaving,” said Mohammad, 20, standing in the street outside a building reduced to rubble in an earlier Israeli air strike near the centre of Gaza.

Mosques broadcast the message: “Hold on to your homes. Hold on to your land”.

“We tell the people of northern Gaza and from Gaza City, stay put in your homes, and your places,” Eyad Al-Bozom, spokesman for the Hamas Interior Ministry, told a news conference.

Rockets are launched from the Gaza Strip towards Israel, as seen from Ashkelon, in southern Israel. PHOTO: Reuters

US President Joe Biden said consultations were under way with regional governments on the humanitarian crisis in Gaza as trapped Palestinians endured a power blackout and shortages of food and water amid fierce Israeli bombing.

The United Nations and other organisations warned of a disaster if so many people were forced to flee, and said the siege of the enclave should be lifted to let in aid.

The situation in Gaza has reached a “a dangerous new low”, UN Secretary General Antonio Guterres said on Friday. “We need immediate humanitarian access throughout Gaza, so that we can get fuel, food and water to everyone in need. Even wars have rules.”

Earlier, a UN spokesperson Stephane Dujarric said it would be impossible for Gazans to obey Israel’s order to leave the north without “devastating humanitarian consequences”, prompting a rebuke from Israel that the UN should condemn Hamas and support Israel’s right to self-defence.

“The noose around the civilian population in Gaza is tightening. How are 1.1 million people supposed to move across a densely populated war zone in less than 24 hours?” UN aid chief Martin Griffiths wrote on social media.

‘Distance yourselves’

White House national security spokesman John Kirby said such a huge evacuation was a “tall order“, but that Washington would not second guess Israel’s decision to tell civilians to get out.

“We understand what they’re trying to do and why they’re trying to do this – to try to isolate the civilian population from Hamas, which is their real target,” he said on MSNBC.

Mahmoud Abbas, president of the Palestinian Authority that is a rival of Hamas, told US Secretary of State Antony Blinken in Jordan that the forced displacement of Palestinians in Gaza would constitute a repeat of 1948, when hundreds of thousands of Palestinians fled or were driven from what is now Israel. Most Gazans are the descendants of such refugees.

Gaza is already one of the most crowded places on earth, and for now there is no way out. Israel has imposed a total blockade, and Egypt, which also has a border with the enclave, has so far resisted calls to open it to fleeing residents.

Austin said military aid was flowing into Israel but that this was the time for resolve and not revenge.

On Friday Blinken travelled to Jordan where he met King Abdullah as well as Abbas, whose Palestinian Authority exercises limited self-rule in the Israeli-occupied West Bank but lost control of Gaza to Hamas in 2007. Blinken later travelled to Qatar, a US ally.

In the West Bank, demonstrators supporting Gaza fought gun battles with Israeli security forces. Palestinian officials said 11 people were shot dead.

There have also been fears of hostilities spreading to new fronts, including Israel’s northern border with Lebanon, where clashes this week have already been the deadliest since 2006.

Reuters news videographer Issam Abdallah was killed on Friday while working in southern Lebanon. Reuters said it was seeking more information and working with the authorities in the region.

Earlier, Reuters reported that Israeli shelling had struck a Lebanese army observation post at the border. The Israeli military said it fired in response to a suspected armed infiltration, which it later said had been a false alarm. Lebanese state media reported that shells struck near Alma Al-Shaab and Dhayra, sites of repeated clashes in the past week.

Israel’s UN envoy said it would investigate what had happened in the area following the journalist’s death.

“We always try to mitigate and avoid civilian casualties. Obviously, we would never want to hit or kill or shoot any journalist that is doing its job,” Gilad Erdan said.