At least 87 people have died after a construction crane collapsed onto the Grand Mosque in the Saudi Arabian city of Mecca.
It's not clear how the accident occurred, but the Saudi Gazette newspaper says that strong winds and rain which have lashed the Arabian peninsula this week may have been a factor.
Social media posts from the scene show wreckage fallen through the roof of the mosque, which is the holiest site in the Islamic world.
The Saudi Civil Defence Authority says that some 184 people have also been injured in the accident, according to the Arab News website.
Local governor Prince Khaled Al-Faisal has called for an investigation in to the incident, the Arab News reports.
The incident happened just before 5.30pm local time, when the mosque was likely to be crowded with worshipers attending Friday prayers. A site of pilgrimage, there would also be large numbers of faithful performing their ritual walk around the Kaaba, the ancient stone building at the Grand Mosque's centre.
Mecca is currently preparing for the annual Hajj pilgrimage, in which three million people are expected to travel to the city. The authorities have recently spent several years expanding the Grand Mosque to allow more pilgrims to worship in safety.