The incident on Sunday came during Ramadan, the most sacred month for Muslims, when the Grand Mosque is among the most crowded places in the world, with tens of thousands performing minor Umrah pilgrimage or praying there, presstv.com wrote.
The Saudi Press Agency quoted officials as saying that the accident took place in a worksite in the mosque that was far away from the path of worshipers and visitors.
It cited overloading of the machinery as the cause of the incident in which the arm of the crane collapsed at the construction site.
The accident revived bitter memories of a crane collapse at the Grand Mosque in 2015, which left at least 107 pilgrims dead and more than 230 others injured.
It forced the Saudi Binladen Group to stop expansion projects in the mosque compound for two years.
That incident and a deadly human crush two weeks later brought diplomatic relations between Iran and Saudi Arabia to a head, before Riyadh cut ties with Tehran following strong protests against the kingdom's execution of prominent Shia cleric.
In the second incident, hundreds of pilgrims lost their lives in Mina after two large masses converged at a crossroads during the symbolic stoning of Satan.
Saudi Arabia claims nearly 770 people were killed in the incident, but officials at Iran’s Hajj and Pilgrimage Organization say about 4,700 people, including more than 460 Iranian pilgrims, lost their lives.
Those incidents as well as frequent fires at the tent camps of pilgrims have raised serious questions about the competence of Saudi authorities in charge of organizing annual Hajj rituals.