UN Secretary-General Antonio Guterres on Monday warned that the bombarded Gaza Strip was becoming a “graveyard for children,” as he urged an immediate ceasefire in the Israel-Hamas conflict.

“The unfolding catastrophe makes the need for a humanitarian ceasefire more urgent with every passing hour,” he told reporters at the UN headquarters in New York.

“The parties to the conflict — and, indeed, the international community — face an immediate and fundamental responsibility: to stop this inhuman collective suffering and dramatically expand humanitarian aid to Gaza,” he said.

“The nightmare in Gaza is more than a humanitarian crisis. It is a crisis of humanity.”

Israel’s strikes have killed 10,222 people, including more than 4,000 children, in the densely populated and besieged Gaza Strip, according to the Hamas-run health ministry.

Guterres also deplored the killings of media workers. According to the New York-based Committee to Protect Journalists, at least 36 journalists and media workers have been killed.

“More journalists have reportedly been killed over a four-week period than in any conflict in at least three decades,” Guterres said, adding that 89 UN aid workers have also been killed.

Guterres was formally launching a recently announced $1.2 billion UN humanitarian appeal to help 2.7 million Palestinians over the entire Gaza Strip and parts of the occupied West Bank and East Jerusalem.