The UN chief on Monday decried events in Gaza since Oct. 7, calling them a "killing of civilians that is unparalleled and unprecedented" since he took office.
"What is clear is that we have had in a few weeks thousands of children killed, so this is what matters," Antonio Guterres said in New York while presenting a new UN environmental report. "We are witnessing a killing of civilians that is unparalleled and unprecedented in any conflict since I am secretary general."
It is important to be able to transform the tragedy into an opportunity, Guterres said, adding: "It is essential that after the war we move in a determined, and the reversible way to a two-state solution."
He also said he has been "very clear" in denouncing violations of international humanitarian law and violations of the protection of civilians.
Asked why he has not called Israeli attacks "war crimes," Guterres said he did not have a "mandate" to do so.
The Gaza Strip has been under heavy bombardment since the Palestinian group Hamas launched a surprise offensive against Israel on Oct. 7.
Since Israel began its attacks on Oct. 7, at least 13,000 Palestinians have been killed, including over 9,000 women and children, and more than 30,000 others have been injured, according to the latest figures from the Palestinian Health Ministry.
Thousands of buildings, including hospitals, mosques, and churches, have also been damaged or destroyed in Israel's relentless air and ground attacks on the besieged enclave.
An Israeli blockade has also cut Gaza off from fuel, electricity, and water supplies, and reduced aid deliveries to a small trickle.
The Israeli death toll, meanwhile, is around 1,200, based on official figures.