The Arab coalition fighting rebels in Yemen says it will investigate an attack on a funeral ceremony in the capital, Sanaa, that killed at least 140 people and wounded more than 500.
The alliance, which is made up of Saudi Arabia and other Arab states battling Houthi rebels, said that "its troops have clear instructions not to target populated areas", and that it was ready to launch a probe with the United States into Saturday's "regrettable and painful" attack.
"The coalition will immediately investigate this case along with Joint Incidents Assessment Team in Yemen and experts from the United States who participated in previous investigations," it said in a statement carried by the Saudi Press Agency on Sunday.
The alliance's statement came after the US said on Saturday it would review its support for the Arab coalition in Yemen.
The death toll was one of the largest in any single incident since the Arab alliance began military operations to try to restore President Abd-Rabbu Mansour Hadi to power following his ousting by the Houthis in March 2015.
Eyewitnesses said four air strikes targeted a reception at the grand hall of ceremonies in Sanaa, where hundreds of mourners, including military and intelligence officials, had gathered to take part in a funeral ceremony for the father of Brigadier Jalal al-Ruweishan, interior minister in the self-proclaimed Houthi government.
Rweishan had sided with the Houthi movement when President Hadi fled Yemen after the Houthis advanced on his headquarters in the southern port city of Aden in March 2015.
Hakim al-Masmari, the editor of the Yemen Post, told Al Jazeera that Sanaa's mayor, Abdul-Qadir Hilal, was confirmed killed, but the fate of Ruweishan and other senior Houthi officials remained unclear.
"I watched the air strikes, which took place barely 1.5km from my house. They first used a normal missile which pierced the roof. The second was an incendiary missile, burning the whole inside of the hall," Haykal Bafana, a Yemeni analyst based in Sanaa, said.
"The third was a missile on first responders," Bafana added.
Eric Jeunot, head of mission at Doctors without Borders (MSF), told Al Jazeera that the medical charity was dealing with hundreds of wounded patients in the wake of the attack.
"Most of the patients are suffering from burns and shrapnel injuries. Most of them require surgery and many are in a critical situation."
Stephen O'Brien, the UN Under-Secretary-General for Humanitarian Affairs and Emergency Relief Coordinator, said he was "horrified and extremely disturbed" by the attack and called for a prompt and "impartial" probe.
"This horrendous and heinous attack displayed an utter disregard for human life," O'Brien said.
"I call on all parties to protect civilians and stop using explosive weapons or conducting aerial bombardments in civilian-populated places in Yemen. Surely enough is enough," he added.
The Arab coalition has been providing air support for Hadi's forces in a civil war that has killed more than 10,000 people and displaced more than three million.
The alliance has been blamed for several attacks on medical centres, including some run by international aid group MSF, schools, factories and homes in the past 18 months, which have killed scores of civilians.
In August, MSF said it was evacuating its staff from six hospitals in northern Yemen after a coalition air strike hit a health facility operated by the group, killing 19 people.
However, in recent months, the alliance has come under increasing international scrutiny over civilian deaths.
In August, Doctors Without Borders (MSF), one of handful of international aid groups operating on the ground in Yemen, evacuated its staff from the north of the country after a coalition air strike hit a health facility operated by the group, killing 19 people.
The coalition, which says it does not target civilians, has expressed deep regret over the decision and said it was trying to set up "urgent meetings" with the medical aid group.
Last month, a report by the Yemen Data Project, a group of security and human rights researchers, found that more than a third of air strikes hit civilian sites including schools, hospitals and mosques.
Out of the more than 8,600 air raids examined, the report found that 3,577 were listed as hitting military sites and 3,158 non-military, while 1,882 strikes were classified as unknown.