Water sprays on posts across the plain provided a thin mist and some relief from the midday heat.
Prayers for forgiveness
"The conditions are fine. This event brings us together from all countries in the world," Nagat Ahmed, an Egyptian woman from the Nile Delta province of Dakahlia, said.
Asghari Saba Ansari, from Crawford Market near the Indian capital Delhi, said her family had found space on the tarmac, between a parked bus and a large 4WD vehicle.
"We have been here for three hours now and everybody is co-operating. No one has troubled us. We have been praying for forgiveness for any mistakes we have made, for a better life and the good of all Muslims," she said.
Saudi authorities say more than 1.6 million people from 181 different countries have entered the country for the event, the largest annual religious gathering in the world.
Prince Nayef bin Abdel Aziz, the Saudi interior minister, said the figure was a three per cent increase on last year.
He said that several hundred thousand residents of the kingdom, both Saudi and expatriate, were also taking part.
Mountain of Mercy
Some of the pilgrims spent the night on Mount Arafat, also known as Jabal al-Rahma or the Mountain of Mercy.
The afternoon at Arafat, known in Arabic as the wuqouf or "standing", is an essential part of the pilgrimage.
The noon prayer and sermon at the Namera Mosque is a major event, evoking the sermon which Muslims believe Prophet Muhammad made from the hill in the year of his death in 632.
|The afternoon at Arafat is known as the wuqouf|
and is an essential part of the Hajj [AFP]
Grand Mufti Sheikh Abdel-Aziz Al al-Sheikh, Saudi Arabia's state-appointed religious authority, prayed in a sermon before hundreds of thousands for the prosperity of Muslims and Saudi Arabia's rulers, and condemned Islamist violence.
"O Muslims, reject this terrorism, and young people should be careful not to become a means for ruining your countries and your people," he said.
As darkness fell, the crowds moved towards Muzdalifa, the next stage in the pilgrimage, along a special highway served by huge floodlights.
There they will collect small pebbles for throwing at a set of walls on three occasions over the next three days in an act that represents defiance of the devil.