No fewer than 717 pilgrims died and 805 others injured on Thursday in a stampede on the way to the Jamrat complex (stoning site) in Mecca, the News Agency of Nigeria (NAN) reports.
The Saudi Civil Defence Corps said that the exact cause of the accident could not be easily ascertained.
NAN reports that many of the injured were in a semi-conscious state due to harsh summer weather that compounded the problem.
Sirens wailed as ambulances conveyed corpses and injured persons to hospitals, while hundreds of Saudi security forces and hajj volunteers were on hand helping the victims.
Most of the injured were taken to the Mina Emergency Hospital while others were rushed to hospitals in Makkah.
The Jamarat area, where pilgrims perform the symbolic stoning of the devil ritual, had witnessed stampedes in the past.
However, the Saudi authorities had expanded the area by constructing a multi-million-dollar complex to ease the flow of pilgrims.
Pilgrims had spent the night in Muzdalifa and had come to Mina to throw seven stones at one of the three wall-like structures.
NAN recalls that 111 pilgrims had died and 331 others injured in a crane crash in Kaaba, Mecca, on Sept. 11.
Six Nigerians were among the deceased while six others were injured in the incident. (NAN)