UNESCO has condemned an apparent attack on the Yemeni capital's old quarter that killed five people and destroyed homes in the centuries-old heritage site described as a "jewel" of Islamic culture.
Footage of Friday's incident showed crowds gathering the iconic structures in Sanaa's old city, which has been inhabited for more than 2,500 years.
UNESCO director general Irina Bokova said she was "profoundly distressed by the loss of human lives as well as by the damage inflicted on one of the world's oldest jewels of Islamic urban landscape."
"The historic value and memories enshrined in these sites have been irreparably damaged or destroyed," Bokova said.
"This destruction will only exacerbate the humanitarian situation and I reiterate my call to all parties to respect and protect cultural heritage in Yemen."
The Arab coalition at war with Houthi rebels in Yemen denied claims that one of its planes had carried out an air strike there.
The spokesman for the coalition, Brigadier General Ahmed al-Assiri, said there was no operation on the site, suggesting instead that a rebel ammunition cache may have exploded.
The incident occurred a day before Yemen's warring factions are to meet for UN-sponsored talks in Geneva in their first bid to break a deadlock after more than two months of Saudi-led air strikes.
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"For sure we did not conduct any operation inside (the) city," Assiri told the AFP news agency.
"We know that those sites are very important."
He said rebels may have been hiding weapons or ammunition in the area. "Several days before they had an explosion in one of their storage" areas, he said of the Houthi rebels. "So it could be one of these."
Sanaa's old city has been a major centre for the propagation of Islam, boasting more than 100 mosques, 14
public baths and more than 6,000 houses built before the 11th century.
It was inscribed on UNESCO's World Heritage List in 1986.