Amid reports its collapse at the Islam holy site was triggered by strong winds during a thunderstorm, Saudi authorities have vowed to investigate what caused the accident.

New footage, the majority of which is too gruesome to show, has now emerged of the moment the construction crane fell and crashed through the mosque's ceiling. It comes as local Saudi media claimed the death toll had risen to 111 and the number of injured 331.

In the short video, dozens of people can be seen wandering through the building as its foundations are visibly shaking. An instant later, many are crushed as the huge crane lands on them.

Meanwhile, the region's governor has today filed an investigative report into the incident, official media said. Prince Khaled al-Faisal 'has submitted today the results of the investigation', according to the Saudi Press Agency.

Faisal sent the findings to Crown Prince Mohammed bin Nayef for presentation to King Salman, it said, without disclosing any contents.

Salman vowed yesterday to reveal what caused the crane to topple into a courtyard of the Grand Mosque, where hundreds of thousands of Muslims have converged ahead of the hajj pilgrimage later this month.

'We will investigate all the reasons and afterwards declare the results to the citizens,' Salman said after visiting the site, one of Islam's holiest.

Prince Faisal ordered a probe as soon as the tragedy struck.

The investigative committee was headed by Hesham al-Faleh, an adviser to Prince Khaled, who was under orders to submit the findings urgently.

Nationalities of most of those killed have still not been revealed but they included Indians, Indonesians and a Thai. Among the injured were Iranians, Turks, Afghans, Egyptians and Pakistanis.

The crane which collapsed during the thunderstorm was one of several working on a multi-billion-dollar expansion of the mosque to accommodate mounting numbers of faithful

Yesterday, people simply walked by the toppled crane as they gathered at the holy place, some taking pictures behind the barriers, some posing with the scene of the disaster in the background.

Later on, guards sat on chairs in the middle of a brilliant white floor, surrounded by visitors behind barriers, and just metres away from huge craters in the floor which was covered with victims of the disaster.

Some critics have claimed that the authorities were negligent in allowing a series of cranes to tower over the site, as hundreds of thousands of Muslims converge at the holy site for the annual hajj pilgrimage.

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.

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.

'The speed of the wind was not normal,' he said. 'There was no way for people to know that the crane was about to collapse for them to scramble,' he added.

(dailymail.co.uk)