A fire broke out Friday night at the Mosque-Cathedral of Cordoba, damaging part of the UNESCO World Heritage Site, Spanish authorities said.

The blaze, reported at 9:15 p.m. local time, originated from a suspected mechanical issue in one of the building’s chapels, according to Spanish newspaper El Mundo. 

“The first information suggests that the fire was caused by a mechanical sweeper that was in one of the rooms used as a warehouse within the enclosure,” the newspaper reported.

Video footage showed flames engulfing part of the medieval structure. 

Firefighters responded quickly, and the city’s mayor, Jose Maria Bellido, thanked them on X. The fire was “extinguished thanks to the swift action of the firefighters,” Bellido said, adding they would remain on site overnight.

The Mosque-Cathedral, originally built as a mosque in the 8th century under the Umayyad Caliphate, is considered a masterpiece of medieval Islamic architecture, with grand halls, intricate mosaics, domes, arches and a large courtyard. 

The city of Cordoba was the capital of the Muslim-ruled Iberian Peninsula, known at the time as al-Andalus. It was a flourishing Muslim-led hub of philosophy, science and culture in medieval Europe.

Muslim rule in Spain ended in 1492 with the Reconquista, after which the mosque was converted into a cathedral by King Ferdinand I of Spain. It has been a UNESCO World Heritage Site since 1984.