By Jonathan Wright
MECCA, Saudi Arabia (Reuters) - The annual haj pilgrimage began in Mecca on Monday when hundreds of thousands of Muslim pilgrims put on white clothes, packed their bags and left for a tented encampment on the edge of the holy city.
In central Mecca, some latecomers performed the ritual walk seven times around the Kaaba, the ancient cubic shrine which all Muslims face when they perform their daily prayers.
More than 1.6 million pilgrims have come to Saudi Arabia from abroad for the haj, the largest regular religious gathering in the world and an obligation which all Muslims should perform at least once if they can afford it.
Pilgrims from within Saudi Arabia -- Saudis or foreign workers --- will take the total to well over 2 million.
By the evening they should all have reached the Mina area east of Mecca, the first overnight stage in an itinerary which will bring them back to Mecca later this week.
Some of them walked, carrying their bags, while others took buses moving slowly through the crowds.
This year the Saudi authorities are trying to crack down on the number of pilgrims who slip into the holy city without permits and add to massive crowd control problems.
On the road to Mecca from the large Red Sea port of Jeddah, police checked the papers of all drivers and passengers to make sure they had good reasons for travelling to Mecca.
Pilgrims are easy to detect because of a traditional requirement that male pilgrims put on special clothes well before they reach Mecca. A pilgrimage does not count if they enter the state of "ihram", or ritual purity, too late.
Saudi authorities say they had made every possible preparation for the pilgrimage, which King Abdullah protects and sponsors in his role as Custodian of the Two Holy Mosques.
SHOW OF STRENGTH
An innovation this year is the construction of a third level at the Jamarat Bridge, from which pilgrims throw pebbles at a concrete wall, representing defiance of the devil.
The bridge near Mina has been one of the worst bottlenecks for traffic. In January 2006, 362 people were crushed to death on the bridge, the worst haj tragedy in 16 years.
Given the political turmoil in the Middle East, the Saudis are also on the alert for any political activity by pilgrims, but the first stages this year have been largely trouble-free.
The Saudi interior ministry put on a show of strength on Saturday with a parade by police units including counter-terrorism commandos in balaclava helmets.
But Interior Minister Prince Nayef bin Abdul-Aziz told a news conference there was no link between this year's haj and 208 men detained last month in the latest of a series of sweeps against suspected militants in Saudi Arabia.
Prince Nayef confirmed that Iranian President Mahmoud Ahmadinejad will attend the rites this year, the first time an Iranian president has done so.
The king's invitation to Ahmadinejad could reflect a tentative improvement in relations between Saudi Arabia, the dominant Sunni Muslim power in the Gulf, and Shi'ite Muslim Iran on the other side of the strategic waterway.
The Saudi government works closely with the United States, while Tehran and Washington have been mutually hostile since the Islamic revolution in Iran in 1979.
Pilgrims see the haj as an affirmation of Muslim unity and solidarity, bringing together people of different languages and ethnicities united only by belief in a single god.
On a personal level, many of them say they are also seeking forgiveness for sins of which they have repented.
"A good haji (pilgrim) will go home like a new-born child. All his sins are forgotten," said Nigerian sociology professor Baffa Aliyu Umar, who is on his fourth haj.
(Editing by Michael Winfrey)
