The U.N. human rights office said Tuesday it has verified the killings of 136 Yemeni civilians and other non-combatants in airstrikes carried out over 11 days this month by a Saudi-led military coalition batting Yemen’s Shiite rebels.

Spokesman Rupert Colville of the Office of the High Commissioner for Human Rights said U.N. officials are “deeply concerned” about a surge in civilian casualties from airstrikes following the killing in early December of Yemen’s former president, Ali Abdullah Saleh.

Saleh was killed by the rebels, known as Houthis, after apparently switching alliances and turning against his former allies. Colville said the killings occurred between Dec. 6 and Dec. 16 in four northern provinces.

The airstrikes, which also injured 87 people, hit Yemen’s rebel-run TV channel, a hospital in the Red Sea port city of Hodeida, and a wedding party — a strike that killed one woman and nine children, the rights office said.

Seven strikes on a police compound in Sanaa on Dec. 13 killed at least 43 people when the compound’s prison grounds were hit, the office said. All those victims were reportedly detainees loyal to President Abed Rabbo Mansour Hadi, who is supported by the coalition.

“I think one can assume that that was a mistake,” Colville said. “They weren’t intending to kill prisoners from their own side.”

After originally indicating that the 11-day confirmed death toll was 115, Colville later said it had increased to 136 to include a strike on Friday on a farmhouse in Hodeida governorate that left 20 people dead — including 14 children.

Meanwhile, hundreds of world figures urged the leaders of the United States, France and Britain on Tuesday to stop “stoking the flames of war” in impoverished Yemen. The statement, signed by 355 high-profile figures, marked the 1,000th day of the war, which has turned the poorest Arab country into the world’s largest humanitarian crisis.

The signatories included eight Nobel peace laureates, religious leaders, Western lawmakers and rights defenders, as well as U.S. Congresswomen Barbara Lee and Pramila Jayapal, and Congressman Ro Khanna, all Democrats.

“To prevent further catastrophe and famine, Yemen needs an immediate cease-fire; an end to all blockages on access for food, fuel and medical supplies; and investment in a new, inclusive peace process,” the statement read.

It appealed to President Donald Trump, British Prime Minister Theresa May and French President Emmanuel Macron.

“If you don’t want the burden of the lives of thousands more Yemeni children on your hands, then the time to act is now. Yemen can’t wait any longer,” it said.

The appeal also called on the U.N. Security Council to press Saudi Arabia and its ally the United Arab Emirates, the main pillars of the coalition, to end the war in Yemen. The U.S.-backed coalition is seeking to restore Yemen’s internationally recognized government to power.

Over the past three years, more than 10,000 people have been killed and three million displaced amid the Saudi-led coalition’s air campaign against the Iranian-backed Houthis and their allies.

(AP)