UN Secretary-General Antonio Guterres demanded that Israel reopen two key land crossings to enable desperately needed aid supplies to reach Palestinians in Gaza.

“The closure of both the Rafah and Kerem Shalom [Karem Abu Salem] crossings is especially damaging to an already dire humanitarian situation. They must be reopened immediately,” he said on Tuesday.

Israel seized the Gaza side of the Rafah crossing earlier on Tuesday, as ceasefire talks with the Palestinian group Hamas remain precarious.

Hamas said late on Monday that it had accepted a Gaza ceasefire proposal put forward by Qatari and Egyptian mediators. Israel said the proposal fell short of Israeli requirements and that it would send a delegation to meet the mediators.

Guterres warned an assault on Rafah, where more than 1.4 million displaced Palestinians are sheltering, would “be a strategic mistake, a political calamity and a humanitarian nightmare”.

Amnesty International called on the international community to pressure Israel to immediately halt its ground operations in Rafah and ensure unfettered access for humanitarian aid in Gaza.

The group’s senior director of research, advocacy, policy and campaigns, Erika Guevara-Rosas, said Israel’s long-threatened, large-scale ground operation in Rafah would further compound “the unspeakable suffering of the Palestinians in Gaza”.

Israel’s Defence Minister Yoav Gallant visited troops said the Rafah operation would continue until Israel “eliminates” Hamas in Rafah and the rest of Gaza.

But he said Israel is willing to make “compromises” to bring captives home. “If that option is removed, we will go on and ‘deepen’ the operation,” he said. “This will happen all over the Strip – in the south, in the centre and in the north.”

‘It’s not safe’

Red Crescent sources in Egypt said aid shipments via the Rafah crossing had completely halted on Tuesday.

“The Israeli occupation has sentenced the residents of the Strip to death,” said Hisham Edwan, spokesperson for the Gaza Border Crossing Authority.

In Geneva, UN humanitarian office spokesperson Jens Laerke said “panic and despair” were gripping the people in Rafah.

He said that under international law people must have adequate time to prepare for an evacuation, and have a safe route to a safe area with access to aid. This was not the case in the Rafah evacuation, he said.

“It’s littered with unexploded ordnance, massive bombs lying in the street. It’s not safe,” he said.

The comments came after an Israeli government spokesperson called on international organisations to evacuate from areas of Rafah where military operations are continuing.

The spokesperson said that aid is continuing to flow into the enclave despite the military operation.

Aid groups have warned for months that Israel’s restrictions on aid deliveries into Gaza are exposing the population to severe hunger. Famine has already taken hold in the territory’s north.

Hamas has accused Israel of trying to undermine efforts to secure a ceasefire after Israel’s seven-month-long assault on Gaza that has laid waste to the Strip and left hundreds of thousands of its people homeless and hungry.

Israeli army footage showed tanks rolling through the Rafah crossing complex and the Israeli flag raised on the Gaza side.

Israel sends delegation to Cairo

The seizure of the Rafah crossing comes after weeks of pressure from several of Israel’s key Western allies to hold off from a ground assault on Rafah without a plan for the safe evacuation of civilians.

Many of the people now in Rafah were struggling to find a safe place to go in the tiny strip of land, which has been bombarded almost non-stop since October 7.

Families have been crammed into tented camps and makeshift shelters, suffering from shortages of food, water, medicine and other essentials.

Residents said Israeli tanks and planes attacked several areas and houses in Rafah overnight on Monday and on Tuesday. The Gaza Health Ministry said Israeli attacks across the enclave had killed 54 Palestinians and wounded 96 others in the past 24 hours.

At least 34,789 Palestinians have been now killed in the assault, the Gaza Health Ministry said.

Meanwhile, Guterres appealed to Israel and Hamas to spare no effort to secure a truce deal.

Hamas said late on Monday that it had told Qatari and Egyptian mediators handling the indirect talks that it had agreed to a ceasefire proposal but Israel said the terms did not meet its demands.

However, the various players appeared willing to talk again on Tuesday.

A team of mid-ranking Israeli officials will travel to Cairo in the coming hours to assess whether Hamas can be persuaded to shift on its latest ceasefire offer, a senior Israeli official said.

The official also reiterated that the current Hamas proposal was unacceptable to Israel.

“This delegation is made up of mid-level envoys. Were there a credible deal in the offing, the principals would be heading the delegation,” the official told the Reuters news agency, referring to the senior officials from the intelligence services Mossad and Shin Bet who are leading the Israeli side.

A Palestinian official close to mediation efforts told Reuters that a Hamas delegation may arrive in Cairo later on Tuesday or on Wednesday to discuss the ceasefire proposal.

Any truce would be the first pause in fighting since a week-long ceasefire in November during which Hamas freed dozens of captives and Israel released 240 Palestinians it was holding in its jails.

Since then, all efforts to reach a new truce have foundered over Hamas’s refusal to free more captives without a promise of a permanent end to the conflict, and Israel’s insistence that it would only consider a temporary pause in its assault.