By Inal Ersan
MENA, Saudi Arabia (Reuters) - Hundreds of thousands of Muslim pilgrims marched through a maze of cement and plastic crowd control blocks as they headed to Mena near Mecca to stone walls symbolizing rejection of temptation on Monday.
The barriers are designed to direct the flow of the worshippers to three spots where they will throw pebbles at walls that represent the devil in the most accident-prone ritual of the annual haj pilgrimage.
Tens of thousands of the more than two million pilgrims boarded buses, pick up trucks and even stood in the back of lorries to travel from Muzdalefa where they spent their night, mostly in tents or in the open, after gathering pebbles.
"Let's make the accidents at the stoning part of history, may it never return," state-run Saudi television said in a programme about improvements to the Jamarat bridge facilitates that are designed to reduce the chance of disaster.
The bridge has been the scene of a number of deadly stampedes -- 362 people were crushed to death there in 2006 in the worst haj tragedy since 1990.
Pilgrims will spend the next three days visiting the bridge as well as revisiting the Grand Mosque in Mecca.
Saudi authorities have made renovations to ease the flow of pilgrims, adding a fourth platforms from which to throw stones.
They are also making appeals to pilgrims this year to throw their stones at any time of day rather than only in the afternoon, as Saudi clerics have often insisted in the past.
"This crowdedness is really scary," said Umm Mohammad, a Syrian pilgrim, as she watched the twisted trail crowded with pilgrims from the top of a flyover in Mena. "God willing no one will be hurt."
Meanwhile at the Grand Mosque, many pilgrims were circling the Kaaba, a cube-shaped structure that Muslims believe was first built by biblical patriarch Abraham.
"Thank God for letting me visit his house," said a pilgrim as he navigated his way through the crowd in the mosque, to which Islam's holy book the Koran refers as the house of God.
Saudi Arabia has not so far reported any glitches in the haj, a logistical feat of organisation that has been marred in previous years by deadly fires, hotel collapses, police clashes with protesters and stampedes caused by overcrowding.
Monday is the start of the Eid al-Adha, or feast of the sacrifice, commemorating the willingness of biblical patriarch Abraham to sacrifice his son for God.
Some pilgrims who had done the first round of three stoning rituals late on Sunday, performed Eid prayers at the Grand Mosque, after men had their heads shaved, marking the end of the haj climax.
"It will take three minutes a head," said a man ushering people to a frantically busy barber shop near the mosque while men chose between a machine trim, or the razor.
Although no major accidents have been reported this season, the Saudi authorities were not able to stop some political activities, which pilgrims had been called on to avoid.
Iranian television showed Iranian pilgrims at Arafat chanting "Death to America" and "Death to Israel" on Sunday. Ayatollah Mohammad Mohammadi Reyshahri, head of Iran's haj mission, said Islam was now resurgent, despite some Muslims' despair "in the face of Western civilization's onslaught."
On Sunday, pilgrims spent the day in prayer at Arafat 15 km (10 miles) east of Mecca at the climax of haj, a duty for every able-bodied Muslim once in a lifetime and one of the largest manifestations of religious devotion in the world today.
The haj retraces the path of Prophet Mohammad 14 centuries ago after he removed pagan idols from Mecca, his birthplace, and years after he started calling people to the new faith, which is now embraced by more than one billion people worldwide.
As part of its intensified crowd control measures, the government has been tougher this year in preventing Saudis and foreign residents taking part without official haj permits.
Saudi media said a record 1.72 million pilgrims had come from abroad this year, and more than half a million had come from inside the country, home to Islam's holiest sites.
(Editing by Matthew Jones)