Riyadh  - Around three million Muslims have gathered on Sunday on Mount Arafat in Saudi Arabia to perform one of the most important practices in the hajj pilgrimage.

During this day, which coincides with the 9th day of the last month in the Muslim lunar calendar, pilgrims spend hours praying and reading the Holy Koran.

Amid tight security, pilgrims headed to Arafat, which lies in the west of the Kingdom, late on Saturday.

Also known as the Mount of Mercy, it is the place Islam's prophet Mohammad is said to have delivered his Farewell Sermon to the Muslims who had accompanied him for the Hajj, 14 centuries ago.

At sunset pilgrims - on foot, in wheelchairs or by bus - will descend Arafat and head to al-Muzdalifa, where they pick up pebbles to stone three pillars that symbolize the devil.

The stoning ritual coincides with the Eid al-Adha, or the feast of sacrifice, which starts on Monday.

During the hajj, pilgrims dress in simple white robes, marking ihram, or ritual purity. Hajj, the fifth pillar of Islam, should be carried out at least once in a lifetime, if the person can afford it.

Other practices of the hajj include walking counter-clockwise seven times around the cube-shaped building the Kaaba, towards which Muslims face to pray, running back and forth between the hills of al- Safa and al-Marwa; and drinking from the blessed Zamzam Well.

Following the annual tradition, the Kaaba's cover, known as the kiswa, was replaced on Sunday with a new one, that cost 20 million riyals (around 5.4 million dollars).

The kiswa is a black and gold silk curtain embroidered with calligraphy with Koranic verses. (dpa)