"Here I am Allah, answering your call," chanted a chorus of pilgrims as the huge crowd moved on foot or by bus along the road linking Makkah to Mina, which has been transformed into a vast site of fireproof tents.

The journey began mid-morning, proceeding with calm and without major incident amid mild weather conditions.

The faithful will spend the day here in prayer and meditation. They took part in the weekly Friday prayers, which this year coincided with the huge religious gathering in Mina.

The men are clad in a two-piece seamless white cloth in keeping with tradition, while women are fully covered except for the hands and face.

The journey to Mina is taking place amid the tightest security measures, imposed by the Saudi authorities to ensure the safety of the near two million pilgrims.

The authorities have warned that they will not tolerate any attempt to undermine security during the Hajj. In early November they said they had foiled a plot to attack pilgrims gathered in Makkah during the Muslim fasting month of Ramadan and shot dead two "terrorists."

In the Saudi capital, Riyadh, 700km from Makkah, five Saudi security men and the father of a wanted militant were shot dead by unknown gunmen during a raid on Thursday, after the militant was arrested.

Before dawn today, the faithful will move towards Mount Arafat, a revered place in Islam, for the culmination of the Hajj, symbolising the Final Judgement at the scene of the Prophet Hazrat Mohammed (SM)'s last sermon 14 centuries ago.

The faithful will then return to Mina to sacrifice an animal, generally sheep, marking Eid-ul-Azha, or feast of the sacrifice, celebrated tomorrow.

They will spend two more days in Mina to take part in a symbolic stoning of the devil.