Construction cranes surround the Grand Mosque in the holy city of Mecca in this Jan 5, 2013 file photo. [Photo/Agencies]

The director general of civil defense, Suleiman bin Abdullah al-Amro, told satellite broadcaster Al-Arabiya that the unusually powerful winds that toppled the crane also tore down trees and signs as a storm whipped through the area, AP said.

He denied reports that lightning brought down the red-and-white crane, which was being used for the mosque's expansion, or that some of those killed died in a stampede.

Dai Junfeng, deputy president of Yunnan Islamic Association recorded the massive wind and rainfall from the building he stayed in Mecca on his mobile phone. "I haven't seen extreme weather like that in Mecca for several years and I was told there will be more stormy weather to come," he said. "Local authorities have sealed off parts of the area surrounding the Kaaba for clean up works, so it will be extremely crowded. It will be another disaster if a stampede happens."

On Saturday, Chinese Muslims in Mecca held a service to pray for those who died in the accident.

During the week of the hajj, Muslims converge on Mecca to perform a series of rituals, including the circling of the Kaaba, praying and holding vigil at Mount Arafat, and the symbolic stoning of the devil by throwing pebbles at three pillars in Mina.