The Interior Ministry said 59 people were injured, but nobody would say — or knew — how many more were trapped in the rubble of Lulu'at al-Khair, which housed shops and restaurants and was rented out as a hostel during pilgrimages.
"The rescue operations are still ongoing," Interior Ministry spokesman Maj. Gen. Mansour al-Turki told reporters late Thursday, about nine hours after the collapse. One medic said earlier that he heard cries and moans from inside the debris.
Talha al-Nizi, a Tunisian guide for pilgrims, said his group had just finished midday prayers and returned about 1:10 p.m. to their hotel adjacent to Lulu'at al-Khair, just 200 feet from the Grand Mosque, a focal point of the hajj pilgrimage.
"As I moved to step into my hotel, the whole building collapsed in front of my eyes. The whole street was full of dust," said al-Nizi, who used his mobile phone to capture video and still images of the collapse.
About 1,000 rescue workers, medics and police scrambled over and around the collapsed building. A special unit of the country's anti-terrorism force maintained security, keeping curious bystanders behind a red-and-white police ribbon and patrolling the scene. Six huge generators supported spotlights atop long poles.
"Fortunately the building was almost empty when it collapsed, because most of the residents were in the holy shrine at that time," civil defense Maj. Gen. Alwani, who did not provide his first name, told government-run Al-Ekhbariya television. "Most of the casualties were from the passers-by near the building."
Cranes and bulldozers removed large slabs of concrete, and jackhammers broke up smaller pieces to aid in the clearing of debris. Saad al-Toujeri, head of the kingdom's civil defense forces, said rescuers had lowered cameras and microphones to try to find survivors.
A government official, who did not identify himself, told Al-Ekhbariya that the 40-year-old building's foundations were cracked and weak. Neighboring buildings were evacuated as a precaution, the network reported.
The victims were believed to have come from several countries, including Egypt, Tunisia, the United Arab Emirates and Indonesia. The dead included 11 men, eight women and one unidentified body, al-Turki said.
Tunisia's Religious Affairs Ministry reported that four Tunisians — two women and two men — died in the collapse, and six other Tunisians, all women, were hospitalized.
The wounded were being taken to hospitals in Mecca and Jiddah, about 40 miles to the east.
Qassim Bashir, who works at a hospital in Jiddah, said hundreds of doctors and other medics were brought to Mecca to assist the rescue and recovery efforts. He said he pulled out four bodies in "very bad shape" and that he could hear moaning and crying from inside the debris.
The courtyard of the Grand Mosque encloses the Kaaba, a large cubic stone structure that Muslims face during their five daily prayers.
The Prophet Mohammed was born in Mecca, and the Grand Mosque is central to the Muslim faith and the hajj. Daily prayers are also conducted in the mosque's marble-paved yard, which can hold thousands.
Islam's five pillars demand that followers profess there is one god and Mohammed is his prophet, pray five times daily, give alms, fast daily during the holy month of Ramadan and — if financially able — travel to Mecca at least once in their lifetime.
The number of pilgrims to Mecca has increased elevenfold over the past 15 years. During that time, the Saudi government spent billions of dollars to improve accommodations, transportation and medical facilities for the "guests of Allah."
The gathering has been hit with tragedies frequently in recent years.
The worst hajj-related tragedy occurred in 1990 when 1,426 pilgrims were killed in a stampede in an overcrowded pedestrian tunnel leading to holy sites in Mecca.
In 2004, on the final day of the ceremonies, 251 people were trampled to death when the crowd panicked during the ritual stoning of the devil. Three years earlier, 35 hajj pilgrims were killed in stampede the same ceremony.
In 1998, about 180 pilgrims were trampled to death when panic erupted after several of them fell off an overpass during the ritual. Four years earlier, in 1994, some 270 pilgrims killed in a stampede during the stoning ritual.
During an anti-U.S. demonstration staged by Iranians in 1987, some 402 people, mostly pilgrims from Iran, were killed and 649 were wounded in the crash of a Pakistani jetliner carrying hajj pilgrims Jiddah to Riyadh, the Saudi capital.