Over 140 people were killed and more than 525 injured when Saudi-led coalition airstrike hit a funeral hall packed with thousands of mourners in Yemen’s capital Sana’a in one of the deadliest single attacks of the country’s civil war, a UN official said.

Saudi Arabia said it would launch an investigation into the bombing in Sanaa, without immediately acknowledging that its coalition battling rebels in Yemen is the only force with air power in the conflict.

In the aftermath of the strike, hundreds of body parts were found strewn in and outside the hall. Rescuers collected them in sacks. The strike left the building little more than a shell, with most of its walls and roof gone. Cars parked outside were mangled by the blast.

It is the latest in a string of bombings by the coalition that have struck hospitals, markets and other places civilians congregate.

“The place has been turned into a lake of blood,” said one rescuer, Murad Tawfiq.

Yemeni officials said the dead and wounded included military and security officials from the ranks of the Shiite Houthi rebels fighting the internationally recognized government of President Abed Rabbo Mansour Hadi and their allies, loyalists of former President Ali Abdullah Saleh.

Saturday’s funeral was held for Sheikh Ali al-Rawishan, the father of Galal al-Rawishan, the interior minister in the rebel-led government. Among those killed was Major General Abdul-Qader Hilal, head of the capital’s local council, officials said, while Galal Al-Rishwan was seriously wounded.

In a statement early on Sunday, Saudi Arabia said an investigation would be launched into the strike. Previous investigations by the Saudis have blamed Houthi or rebel forces for gathering near the sites of their attacks.

“The coalition supporting the legitimate government in Yemen has announced that it is aware of reports about the regrettable and painful bombing of the Great Hall in Sanaa today, which led to the killing and injuring of casualties, as reported,” the statement read.

Jamie McGoldrick, the UN humanitarian coordinator in Yemen, said in a statement that the humanitarian community in the country is “shocked and outraged” by the airstrikes. He condemned the “horrific attack” and reminded all parties to the conflict “that under international humanitarian law, they are obliged to protect civilians and civilian infrastructures”. He called for an immediate investigation into the incident.

Initial reports from health officials in Sanaa indicate that over 140 people were killed and more than 525 injured, McGoldrick said.

The incident has prompted the US to initiate an immediate review of its already reduced support for the Saudi-led coalition, White House national security council spokesman Ned Price said. He warned that US security cooperation with Saudi Arabia “is not a blank check”.

Saturday’s attack comes after a Saudi-led coalition March 15 airstrike on a market in Yemen’s northwestern city of Mastaba that killed at least 119 people. Saudi forces reportedly used US munitions in that strike, which at the time was described as the second-deadliest of the Saudi campaign, after a July 2015 attack near a power plant in Mokha that killed at least 120 people.

(With AP inputs)