Saudi Arabia's civil defense authority says at least 62 people have been killed after a crane collapsed on the Grand Mosque in the holy city of Mecca.

The authority announced the collapse and the casualty numbers on its official Twitter account. It says nearly 30 others were injured in the crane collapse on Friday.

Mecca is Islam's holiest site. Pilgrims from around the world have been converging on the city and the mosque for the annual Hajj pilgrimage, which takes place this month.