A stampede broke out Thursday when Muslim pilgrims rushed to fulfill a religious duty known as "stoning the devil," killing more than 150 on the last day of the hajj. Some pilgrims were trampled and others fell to their death.

Most of the victims were from Indonesia and Malaysia and described as elderly men and women, said Saudi officials, who spoke on customary condition of anonymity.The disaster occurred in the searing heat of a desert plain as pilgrims performed the symbolism-laden ritual of "stoning the devil" - hurling pebbles at three pillars symbolizing the temptations of Satan.

Islamic tradition forbids pilgrims from throwing the pebbles before noon. Shortly afterward, crowds surged toward the pillars along a bridge at Mina, three miles from Mecca.

In the havoc that ensued, some pilgrims fell off the bridge, and others were crushed underfoot, the officials said.

Police tried to rescue some of the pilgrims, but the press of the crowd prevented them from getting near.

Saudi officials put the death toll at more than 150 and said other victims included Indians, Pakistanis and Egyptians. The official Saudi Press Agency said 107 had died.

"We seek God's mercy for those who died and patience for their families," the agency said.

Crowds of tens of thousands had struggled with heat that topped 100 degrees. Helicopter crews earlier had hovered overhead to spot pilgrims fainting, and workers on trucks threw bags of chilled water to those making their way to the pillars.

To shield themselves, pilgrims covered their heads with towels or carried umbrellas, some inscribed with "God is great."

Police using loudspeakers had pleaded in Arabic, English, French and Urdu for pilgrims to move along quickly. Other police with batons made room for pilgrims wanting to escape the crowds.

The stampede was the latest tragedy to befall the hajj, which in the past has been bloodied by other stampedes, fires and political protests that turned violent.

Last year, fires driven by high winds tore through a sprawling, overcrowded tent city at Mina, trapping and killing more than 340 pilgrims and injuring 1,500.

In the worst tragedy, 1,426 pilgrims, many of them Malaysians, Indonesian and Pakistanis, were killed in 1990 in a stampede in an overcrowded pedestrian tunnel leading to holy sites in Mecca.