Saudi Arabia's King Salman sanctioned the powerful Saudi Binladin Group Tuesday over the collapse of a construction crane at Makkah's Grand Mosque, which killed more than 100 people days before the hajj pilgrimage.

An investigative committee concluded that the company "was in part responsible" for Friday's tragedy, which killed at least 107 people and injured almost 400 during a severe thunderstorm accompanied by violent winds.

Investigators found that the crane was allegedly "in a wrong position" when the high winds struck, as its main arm should have been lowered, the official Saudi Press Agency said.

"The position of the crane was in violation of operating instructions prepared by the manufacturer," SPA said, adding there had been no response to several letters from concerned authorities about that crane and others.

The firm's executives have been forbidden from leaving the kingdom pending the completion of legal action, SPA said, adding that Salman ordered prosecutors to prepare an indictment.

Until the case is closed, the company will also be excluded from new public projects.

According to Saudi Binladin Group's website, the company has worked on numerous prominent projects in Saudi Arabia including Al-Faisaliah tower in central Riyadh, King Abdullah Financial District, universities and the King Abdul Aziz International Airport in Jeddah.

It has also developed airports and other projects in the Middle East and as far afield as Malaysia.

The construction firm belongs to the family of the late Al-Qaeda leader Osama bin Laden.

Saudi Arabia's ministry of finance has been ordered to "urgently review all current government projects being executed by the Group and others to ensure compliance with safety procedures", SPA said.

Saudi Binladin Group had been working for four years on a multi-billion-dollar 400,000-square-metre (4.3-million-square-feet) enlargement of the Grand Mosque, to accommodate increasing numbers of pilgrims.


Hajj going ahead

That is the equivalent of more than 50 football pitches, and will allow the complex -- Islam's holiest site -- to handle roughly two million people at once.

After visiting the scene on Saturday, Salman vowed that what had happened would become known.

It was the worst accident in a decade surrounding the hajj, which begins next Tuesday and is expected to draw about two million faithful from around the world.

Hundreds of thousands had already converged on the Grand Mosque when the red and white crane, one of several overlooking the site, crashed into a courtyard.

Saudis, Iranians, Nigerians, Malaysians, Indonesians and Indians were among the dead.

Officials say the tragedy will have no effect on preparations for the hajj, one of the world's largest religious events.

An engineer with Saudi Binladin Group told AFP on Saturday that what had happened was an "act of God" and not the result of a technical fault.

"It was not a technical issue at all," said the engineer, who spoke on condition of anonymity.

"I can only say that what happened was beyond the power of humans. It was an act of God and, to my knowledge, there was no human fault in it at all."

The engineer said the crane was the main one used on work to expand the tawaf, or circumambulation area around the Kaaba -- a massive cubed structure at the centre of the mosque that is the focal point of Muslim worship.

"It has been installed in a way so as not to affect the hundreds of thousands of worshippers in the area and in an extremely professional way," he said of the crane.

The crane's heavy hook, which is able to lift hundreds of tonnes, began swaying and moved the whole crane with it, toppling into the mosque, the engineer said.

SPA said that Salman has ordered payments of one million riyals ($267,000) to the family of each deceased, and at least 500,000 riyals to each injured person.