Saudi Arabia says it's treating scores of pilgrims injured during Friday's fatal crane collapse at Mecca. As condolences pour in, Saudi officials said the Muslim annual haj pilgrimage would go ahead.

Blood donors queued in Mecca on Saturday as Saudi hospitals remained on high alert to treat the hundreds injured as the crane toppled on to Mecca's crowded Grand Mosque during a late afternoon storm.

World leaders, including Prime Minister Narendra Modi of India, which is home to millions of Muslims, and US Secretary of State John Kerry, expressed condolences.

Nations list casualties

Indonesia said two of its nationals visiting Mecca had lost their lives and more than 30 were injured. Malaysia said six of its nationals were unaccounted for and 10 were injured.

New Delhi said two Indians were killed. Iran said 15 of its pilgrims were among those in hospital.

Saudi Arabia's health department spokesman in Mecca, Abdel al-Wahab Shalabi, said "all hospitals in the city" were on alert to cope with the wounded, according to the Saudi Press Agency.

Worshippers thronged to the mosque, one of Islam's holiest sites, on Saturday despite closure of some zones around the remains of the red and white crane.

Mecca region governor, Prince Khaled al-Faisal, ordered an investigation into the incident.

"Heavy rain and strong winds of unusually high speed led to the uprooting of trees, the fall of panels and the collapse of the crane," General Suleiman al-Amr, director general of the Civil Defence Authority, told Saudi-owned Al Arabiya TV.

The news agency AFP quoted a worker at Mecca, Abdel Aziz Naqoor, as saying that the disaster could have been worse but for a covered walkway which absorbed the crane's fall.

Irfan al-Alawi, co-founder of the Islamic Heritage Research Foundation and a critic of site redevelopment at Mecca, suggested that authorities had been negligent by having a series of cranes overlooking the mosque.

"They do not care about the heritage, and they do not care about health and safety," said al-Alawi, arguing that building work is wiping away tangible links to the Prophet Mohammed in the area once characterized by steep hills and traditional, low-rise buildings.

Work is under way to expand the area of the Grand Mosque by 400,000 square meters (4.3 million square feet), allowing it to accommodate up to 2.2 million people at once.

One feature is a high-rise hotel with a giant clock - reminiscent of London's Big Ben but much larger - that towers over the site's new Abraj al Bait complex (shown above) to a height of 601 meters.

Part of the clock's inner workings is a computerized chronometer center intended to help Muslims coordinate their daily prayers around the world.

In 2006, several hundred pilgrims were killed in a stampede during the Stoning of the Devil ritual in nearby Mina, following a similar incident two years earlier.

In recent years, the haj has been nearly incident-free. This year's pilgrimage season is due to start on September 21.

ipj/xx (AFP, dpa, AP)