UN chief Antonio Guterres says the levels of death and injury in north Gaza are ‘harrowing’ and calls plight of Palestinians ‘unbearable’.

Israeli attacks have killed more than 50 Palestinians across the Gaza Strip in less than a day, most of them in the north of the enclave which has been the scene of renewed Israeli ground offensive for the past three weeks, leading the chief of the United Nations to call the plight of civilians there “unbearable”.

At least 11 Palestinians were killed and dozens of others wounded after a school in northern Gaza was hit on Sunday.

Reporting from Deir el-Balah in central Gaza, Al Jazeera’s Hind Khoudary said the school is in the middle of the Shati refugee camp, a densely populated camp in northern Gaza.

“The Israeli strike killed at least eight Palestinians, including three journalists and an eight-year-old girl called Zayn al-Ghoul, who was waiting in a queue to receive biscuits from the school,” she said, adding that the death toll could climb as the number of injured was high.

The Israeli military has said it was looking into the report about the strike on the school. The military added that it had killed more than 40 Hamas fighters in the Jabalia area in the past 24 hours, as well as dismantled infrastructure and located large quantities of military equipment.

Hamas has not yet commented on the Jabalia strikes.

Israeli military strikes on the towns of Jabalia, Beit Hanoon and Beit Lahiya in northern Gaza have so far killed about 800 people in the three-week offensive, Gaza’s Ministry of Health said.

UN Secretary-General Antonio Guterres has said he is “shocked by harrowing levels of death, injury and destruction” in north Gaza.

“The plight of Palestinian civilians trapped in North Gaza is unbearable,” Guterres’s spokesman said.

As the death toll from Israel’s retaliatory campaign in Gaza approaches 43,000 since the start of the war on October 7, with the densely populated enclave in ruins, new ceasefire talks have begun in Doha.

On Sunday, the directors of the CIA and Israel’s Mossad intelligence agency travelled to Qatar to meet Qatar’s prime minister to discuss a ceasefire agreement. Egyptian officials are also participating in the talks.

Separately, Egyptian President Abdel Fattah el-Sisi has proposed a two-day ceasefire in Gaza in exchange for Israeli captives with some Palestinian prisoners.

Meanwhile, in Lebanon on Sunday, Israeli forces continued their air raids on the capital Beirut’s southern suburbs after warning residents of several neighbourhoods to leave their homes.

Israeli forces also targeted southern Lebanon. At least eight people were killed and 25 injured in an Israeli air strike on the coastal city of Sidon in southern Lebanon. Lebanese officials said at least 21 people were in Israeli attacks in southern Lebanon.

In retaliation, Hezbollah has been launching attacks across the border into northern Israel.

United States Secretary of State Antony Blinken on Friday met with Lebanese Prime Minister Najib Mikati in London but stopped short of calling for an immediate ceasefire. Washington provides weapons and diplomatic cover to Israel, which has been condemned for violating the rules of war.