Forty-eight people were killed in flash floods as the annual Haj pilgrimage began in the desert kingdom of Saudi Arabia, the Saudi government reported Thursday.
The civil defence authority for the holy Muslim city of Mecca said that Wednesday's "torrential rains and thunderstorms" had turned streets into rivers of mud, destroyed homes and swept away cars.
The 90 millimetres of rain killed 44 in Jeddah and another four in Mecca. Saudi emergency workers rescued more than 900 people, the civil defence authority said in a statement Thursday morning.
The rains had stopped by Thursday morning, as millions of pilgrims gathered in the Arafat Plain, where the Prophet Mohammed gave his last sermon 1,377 years ago on today's date by the Islamic calendar.
Thousands of Iranians staged a brief protest in a massive tent on the plain Thursday.
"Death to America, death to Israel!" they chanted.
"Today we see the hands of the enemies of the Islamic world working more than ever before to sow division among Muslims," Sheikh Mohammed Rashari told Iranian pilgrims.
"Today we are most in need of... harmony and unity among Muslims," he said.
"The enemies of Islam are working throughout the land of Islam," Rashari told Iranians.
"(Jerusalem's) al-Aqsa mosque is in grave danger, the oppressed people of Gaza face unprecedented ethnic cleansing, and Afghanistan is... under the weight of the occupiers, and fratricidal warfare in Yemen adds a new stab to the Islamic nation," he said.
Pilgrims were spending the day reading the Quran and praying. They then continue to Muzdalifah, before celebrating the Eid al-Adha, or the "Feast of the Sacrifice", in Mecca on Friday with a feast of mutton, sharing some with the poor.