Israel has vowed to keep its troops in Gaza until they finish destroying a network of cross-border tunnels, despite sharp UN and US criticism over the Palestinian death toll.

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Speaking on Thursday at a cabinet meeting in Tel Aviv, Prime Minister Benjamin Netanyahu said he would not accept any ceasefire that did not allow troops to continue destroying tunnels used by militants to attack Israel.

“Until now, we have destroyed dozens of terror tunnels and we are determined to finish this mission — with or without a ceasefire,” he said at the start of the meeting.

“So I will not accept any (truce) proposal that does not allow the (military) to complete this work for the security of Israel’s citizens.”

His remarks came after the army confirmed mobilising another 16,000 reservists, hiking the total number called up to 86,000. Israel does not say how many troops are currently fighting inside the Gaza Strip.

But the UN Security Council called for humanitarian pauses in Gaza and renewed its appeal for an immediate ceasefire.

The Council expressed “grave disappointment” that repeated appeals for an end to the fighting had not been heeded.

Meanwhile, Washington said it had agreed to restock Israel’s dwindling munitions supplies, despite increasing international concern over the death toll in Gaza, where 1435 people have been killed in 24 days of violence.

But the White House said there was little doubt Israeli artillery was the source of a “totally indefensible” strike that killed 16 people at a UN school in Gaza on Wednesday and that more can and should be done to ensure the safety of innocent civilians.

UN figures indicate two-thirds of the conflict’s victims are civilians, nearly half them women and children.

The top UN refugee official in Gaza told the Security Council on Thursday that his UNRWA Palestinian refugee agency was stretched to breaking point by the massive humanitarian fallout from the fighting.

Despite rising international calls for a halt to the bloodshed, the Israeli security cabinet decided on Wednesday to press on with the Gaza operation.

There was no let-up on Thursday in the bloodshed with at least 50 Palestinians killed, another 14 dying from injuries suffered in earlier attacks and a growing number of bodies pulled from under rubble in areas near Khan Yunis, medics said.

A senior official telling Haaretz newspaper that a ceasefire was not even close, but an Israeli delegation travelled to Cairo late on Wednesday to discuss a possible ceasefire with Egyptian officials, an official at the airport told AFP.