The world’s largest annual pilgrimage, the hajj, began yesterday with hundreds of thousands of Muslims pouring into the camp of Mina from Mecca to prepare for the solemn rituals.

This year’s attendance is estimated at up to 2.5 million, posing a major headache for the Saudi authorities.

After sunset, pilgrims were still flooding into the vast plain of Mina, a small village about five kilometres east of Mecca, using all possible means to begin their hajj journey.

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

Authorities say permits have been granted to 1.7 million foreign pilgrims, with a further 200,000 issued to pilgrims from within Saudi Arabia and from neighbouring Gulf states.

An interior ministry official said definite numbers will not be announced until tomorrow, the first day of Eid Al-Adha or the Feast of the Sacrifice.

This year has seen a crackdown on pilgrims without the requisite papers as the authorities try to prevent numbers from getting out of hand.

A driver caught transporting unauthorised pilgrims faces a fine of 10,000 riyals ($2,667) for each one. Vehicles with a capacity of fewer than 25 passengers have been banned to streamline the flow of buses.

But the “No permit, no hajj” rule appeared to be widely flouted yesterday as unauthorised pilgrims converged on Mina from across Saudi Arabia.

“We came from Riyadh,” said a Palestinian after being dropped off with two companions at a junction leading to Mina and Arafat, as others arrived in pick-ups, taxis and small buses.

“We skirted the checkpoints by getting out of the car and walking across,” he said without revealing his name, pointing out that once past the highway’s main police checkpoints, getting to the sites is easy.

Buses, choked with both people and luggage inside, carried yet more on their roofs. Tens of thousands of illegal pilgrims sat on the pavements, many with tents. Their sirens screeching, police cars threaded their way into the crowds in an attempt to keep roads open.

“We don’t have permits” said Ramadan Ismael, an Egyptian in his mid-50s who also came from Riyadh.

He said a policeman waived his group of 14 through when they bluntly told him: “We have no permits.”

Meanwhile, pilgrims in licensed groups sat comfortably in their enclosed and well-equipped camps.

Yesterday, Al-Qaeda in the Arabian Peninsula (AQAP) said in an online statement that it is against attacks targeting the hajj.

“We assure our Islamic nation that we are against any criminal action aimed at the pilgrims,” it said.

The passage to Mina marks the official launch of the hajj on the eighth day of the Muslim calendar month of Dhul Hijja.

The day is known as Tarwiah (Watering) as pilgrims in the past stopped at Mina to water their animals and stock up for the trip to Mount Arafat.

At Mount Arafat, some 10 kilometres southeast of Mina, the pilgrims spend the day in prayer and reflection.

After sunset, they move to Muzdalifah, half way between Mount Arafat and Mina, to spend the night.

Tomorrow, they head back to Mina after dawn prayers and perform the first stage of the symbolic “stoning of the devil” and make the ritual sacrifice of an animal, usually a lamb.

On the remaining three days of the hajj, the pilgrims continue the ritual stoning before performing the circumambulation of the Kaaba shrine in Mecca and then heading home.

This year has been incident-free since the pilgrims began gathering in Mecca. The city’s Grand Mosque has been flooded with the faithful, with an estimated 1.7 million taking part in the main weekly Muslim prayers on Friday.

The movement of pilgrims between the holy sites is a major worry for the authorities who have had to deal with deadly stampedes in the past. Saudi Arabia has used its huge oil revenues for massive spending on new infrastructure to ease the flow of humanity.

This year, the first phase of the new Mashair Railway – or Mecca metro – will transport pilgrims between Mina and Mount Arafat through Muzdalifah.

The Jamarat Bridge, where the ritual stoning takes place, has also been expanded to five levels with movement channelled in one direction. Security also remains a concern. On Wednesday, Interior Minister Prince Nayef bin Abdul Aziz said he could not rule out the possibility of an Al-Qaeda attack.