Iran-backed Houthi rebels blamed the Saudi-led coalition
A Saudi-led coalition has promised to investigate an air raid in Yemen that killed more than 140 mourners - after denying it was responsible.
Iran-backed Houthi rebels blamed the coalition for the attack on a funeral hall in the capital Sanaa in which more than 500 were also wounded.
The United States said it was "deeply disturbed" by the airstrike and would review its support for the coalition in the Yemen conflict.
US-Saudi ties are already strained over the kingdom's military intervention in the country, which has been blamed for hundreds of civilian deaths.
After initially denying any responsibility, the Saudi-led coalition said it was ready to launch a probe into the "regrettable and painful" attack.
"The coalition will immediately investigate this case along with...experts from the United States who participated in previous investigations," it said in a statement.
"The coalition is also willing to provide the investigation team with any data and information related to its military operations today, at the incident's location and the surrounding areas."
The UN said aid workers were "shocked and outraged" by the attack on the community hall, where hundreds had gathered to mourn the death of the father of rebel interior minister Jalal al Rowaishan.
It is not clear if Mr Rowaishan or other senior rebel figures were in the building at the time, although Sanaa's mayor Abdel Qader Hilal was reportedly among those killed.
"We are deeply disturbed by reports of today's airstrike on a funeral hall in Yemen, which, if confirmed, would continue the troubling series of attacks striking Yemeni civilians," White House National Security Council spokesman Ned Price said in a statement.
"In light of this and other recent incidents, we have initiated an immediate review of our already significantly reduced support to the Saudi-led coalition and are prepared to adjust our support so as to better align with US principles, values and interests."
Mr Price stressed that "US security cooperation with Saudi Arabia is not a blank cheque", and called on all sides to implement an "immediate" ceasefire.
The UN's emergency relief coordinator, Stephen O'Brien, said the "horrendous and heinous" attack "displayed an utter disregard for human life".
Since March last year, Yemen has been the target of an air campaign launched by an Arab coalition, led by Saudi Arabia.
It was requested by Yemen President Abd Rabbuh Mansur Hadi's government, which is waging a civil war against the Houthi movement.
The Houthis recognise former president Ali Abdullah Saleh as Yemen's legitimate leader.