Tens of thousands of Muslim pilgrims move around the Kaaba, seen at center, inside the Grand Mosque, in Mecca, Saudi Arabia, on Thursday. The annual Islamic pilgrimage draws 3 million visitors each year.[Photo/Agencies]

MECCA, Saudi Arabia - More than 2.5 million Muslim pilgrims on Friday began the rites of the annual hajj pilgrimage, leaving the holy city of Mecca for Mount Arafat, where the prophet Mohammed is believed to have delivered his final hajj sermon.

Dressed in white, they flooded the streets as they headed toward Mina, around 5 kilometers east of the holy mosque.

The day is known as Tarwiah (Watering) Day, as pilgrims traditionally watered their animals and stocked water for their trip to Mount Arafat, some 10 km further on.

Many pilgrims took buses, while others set off on foot for a village that comes to life for just five days a year.

Others were using the Mashair Railway, also known as Mecca Metro, to go to Mount Arafat and its surrounding plains, where they will gather for the Day of Arafat on Saturday. The Chinese-built railway will operate for the first time this year at its full capacity of 72,000 people an hour to ease congestions and prevent stampedes in which hundreds have been killed in past years.

The dual-track light railway connects the three holy sites of Mina, Muzdalifah and Mount Arafat - areas that see massive congestion during the five-day pilgrimage. It will replace 30,000 cars previously used, said project director Fahd Abu-Tarbush.

"The train this year is restricted to the pilgrims coming from inside Saudi Arabia and the Gulf states, as well as 200,000 pilgrims coming from South Asia," Tarbush told AFP.

"Mashair Railway will transport 500,000 pilgrims from Mina, passing by Muzdalifah, reaching to Arafat, in addition to 1 million pilgrims on the Tashreeq days", which are on the 11th, 12th and 13th of the Muslim month of Dhul Hijjah.

About 1.7 million Muslims descended on Mecca from around the world, while between 700,000 and 800,000 pilgrims are from inside Saudi Arabia. The hajj is one of the five pillars of Islam and must be performed at least once in a lifetime by all those who are able to make the journey.