At least 87 people were killed and around 80 injured after a crane collapsed on to the Grand Mosque in the Saudi Arabia's holy city of Makkah, the media reported.
According to Al Arabiya television, Saudi Arabia has been hit by strong sand storms in the last few days.
Saudi authorities have launched a probe into the case, while 15 civil defence and rescue and medical panels have been deployed at the site.
The crane fell down because of the bad weather, which was working on the expansion operations at the Grand Mosque, Xinhua news agency reported.
After the conclusion of the current and final expansion, the mosque could accommodate more than three million worshipers in one hour.
Makkah, the holiest city for Islam, is preparing for the annual Haj, for which hundreds of thousands of Muslims are expected to arrive from all over the world later in September.