More than 140 people have been killed and at least 500 injured in air strikes on a funeral in Sanaa, a senior UN official says.
Local health officials cited by the United Nations said the attack left 140 people dead, however, the Yemen administration's acting health minister Ghazi Ismail said the death toll was 82. The reason for the discrepancy in numbers was not immediately clear.
Mr Ismail said the air strike occurred in the southern part of the city, where a wake was taking place for the father of the administration's interior minister, Houthi-appointed Interior Minister Galal al-Rawishan, an ally of the rebels and of former President Ali Abdullah Saleh.
Mr al-Rawishan had died of natural causes on Friday.
Residents said aircraft fired two missiles at the hall, where hundreds of mourners had gathered to offer condolences.
One missile tore through the building, setting it on fire and sending a large plume of smoke above the area. The other landed nearby.
Witnesses described a scene of carnage, with charred or mutilated bodies strewn around. One rescuer, Murad Tawfiq, described the scene as a "lake of blood", the Associated Press news agency reported.
Ambulances raced to carry the wounded to hospitals, which sent out urgent appeals for blood.
A number of Houthi rebel military and security officials were believed to have been killed in the strike, and damage to the buildings was extensive.
A spokesperson for Yemen's Houthi group condemned the strike as an act of savagery.
"The aggression continues to shed blood in an uncommon savagery and with international collusion that reaches the level of direct participation," the Houthi-run Saba news agency quoted the group's spokesman, Mohammed Abdul-Salam, as saying in a statement.
The death toll was one of the largest in any single incident since the Saudi-led alliance began military operations to try to restore President Abd-Rabbu Mansour Hadi to power following his ousting by the Iran-aligned Houthis in March 2015.
UN humanitarian co-ordinator for Yemen Jamie McGoldrick condemned the "horrific" attack and called for an immediate investigation.
Mr McGoldrick said aid workers who arrived at the scene had been "shocked and outraged" by the air strikes.
The rebel Houthi-run government said a Saudi-led coalition, which is backing the internationally-recognised government of Yemen, was responsible.
"The Saudi aggression committed a major crime today, by attacking a mourning hall for the al-Roweishan family, targeting residents in the hall," Mr Ismail told a news conference in Sanaa.
However, sources in the Saudi-led coalition said there was no Arab coalition role in the strike.
"Absolutely no such operation took place at that target," one of the sources said, citing what he described as confirmation from the coalition air force command.
"The coalition is aware of such reports and is certain that it is possible that other causes of bombing are to be considered. The coalition has in the past avoided such gatherings and (they have) never been a subject of targets."
The Saudi-led coalition has been providing air support for Hadi's forces in a civil war that has killed more than 10,000 people since March 2015 and displaced more than three million.
It had been blamed for several attacks on medical centres, including some run by international aid group Medecins Sans Frontieres (MSF), schools, factories and homes in the past 18 months that has 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.
The coalition, which said it did not target civilians, expressed deep regret over the decision and said it was trying to set up "urgent meetings" with the medical aid group.
US considers cutting support to Saudi-led military campaign
Fighting has intensified since August when UN-sponsored peace talks in Kuwait ended without an agreement.
In a strongly worded rebuke, the White House said it may consider cutting its support to the Saudi-led military campaign, and said it had launched an "immediate review" of its already-reduced support for the coalition.
"US security co-operation with Saudi Arabia is not a blank check," White House National Security Council spokesman Ned Price said.
He said Washington was "prepared to adjust our support so as to better align with US principles, values and interests, including achieving an immediate and durable end to Yemen's tragic conflict".
Iran, Saudi Arabia's main regional rival, described the attack as "a horrific and inhuman crime", and called for the resumption of peace talks among all Yemeni parties.
"To resolve the crisis in Yemen there is no solution but the end of aggression by the brutish Saudi rulers and start of new round of talks that includes all Yemeni sides," Iran's Foreign Ministry spokesman, Bahram Qasemi was quoted as saying by Tasnim news agency.
The government of President Abdrabbuh Mansour Hadi is fighting both the Houthis and forces loyal to Mr Saleh.
Thousand of civilians have been killed since the Saudi-led air campaign started last March, the UN's rights body says.
Nearly three million people have been displaced in Yemen, one of the region's poorest countries, since the war began in 2014.
The Houthis took the capital then, forcing Mr Hadi's government to flee. Some ministers have since returned to the city of Aden.