In pictures: Air strike devastates UNESCO heritage site in Sanaa

The bombing came on the same day as UN-sponsored talks aimed at finding a solution to the Yemen crisis were due to start in Geneva, but the late arrival of one of the Yemeni delegations delayed the negotiations to Monday.

UNESCO condemned the air strike on the historical area which it described as "one of the world's oldest jewels" of Islamic culture, urging warring parties to respect Yemen's heritage.

Residents said the pre-dawn strike was the first direct hit on old Sanaa since the launch of the bombing campaign against Houthi rebels in late March.

The missile reportedly hit the Qassimi neighbourhood, which boasts thousands of houses built before the 11th century.

Although it did not explode, three three-storey houses were destroyed in the attack and at least five residents were killed, including a woman and a child, medics and witnesses said.

"I am 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," UNESCO director general Irina Bokova said, adding: “This destruction will only exacerbate the humanitarian situation and I reiterate my call to all parties to respect and protect cultural heritage in Yemen," she said.

Bokova said she was "shocked by the images of these magnificent many-storeyed tower-houses and serene gardens reduced to rubble".

"The historic value and memories enshrined in these sites have been irreparably damaged or destroyed."

Sanaa's old city, situated in a mountain valley, has been inhabited for more than 2,500 years and was a major centre for the propagation of Islam, boasting over 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.

FRANCE 24 takes a look at some photos posted on Twitter of the destruction.

(FRANCE 24 with AFP)