UN heritage body Unesco has condemned destruction in "one of the world's oldest jewels" of Islamic culture in an apparent air strike in Yemen.
The Old City of Sanaa, a World Heritage site, was hit in a raid on Friday morning which killed five people, residents and medics said.
Residents said it was the first direct hit on old Sanaa since the bombing of Houthi rebels started in late March.
The Saudi-led anti-rebel coalition has denied it carried out the bombing.
Unesco head Irina Bokova said she was "profoundly distressed".
She said the destruction in the oldest part of the capital Sanaa, which included three houses, would "only exacerbate the humanitarian situation".
"This heritage bears the soul of the Yemeni people, it is a symbol of a millennial history of knowledge and it belongs to all humankind," she added.
President Abdrabbuh Mansour Hadi fled to Saudi Arabia in March after being placed under effective house arrest by Houthi rebels who took control of the capital.
More than 2,200 people have been killed and about 10,000 injured since the start of the Saudi-led bombing campaign, according the UN. Riyadh says the offensive is aimed at restoring President Hadi and pushing back the Houthis.
However Saudi coalition spokesman Brig Gen Ahmed al-Assiri said his forces had not bombed the Old City. "For sure we did not conduct any operation inside [the] city," he told AFP news agency.
At the end of May, the ancient city of Marib was bombed a week after the National Museum in Dhamar - containing some 12,500 artefacts - was completely destroyed, according to Unesco.