Hundreds of thousands of Muslims converged on the Mina valley in Saudi Arabia on Tuesday to participate in a symbolic stoning of the devil, the final stage of the annual haj pilgrimage.

Hundreds of thousands of Muslims converged on the Mina valley in Saudi Arabia on Tuesday to participate in a symbolic stoning of the devil, the final stage of the annual haj pilgrimage.

As Muslims around the world celebrated the first day of Eid al-Adha, the feast of sacrifice, the pilgrims, dressed in the ihram, a two-piece seamless white garment, angrily hurled stones at concrete pillars representing the devil.

Although reduced in numbers by half from last year's 3.2 million, the faithful transformed the Mina valley, just outside the holy city of Mecca, into a vast sea of tents.

Some of the 1.5 million pilgrims performing this year's haj -- 1.38 million of them arriving from 188 countries -- began the ritual early in the morning but the number quickly swelled as the day progressed.

The stoning rituals continue until Friday but pilgrims in a hurry can complete it a day early.

The ritual is an emulation of Ibrahim's stoning of the devil at three spots where he is said to have appeared trying to dissuade the biblical patriarch from obeying God's order to sacrifice his son, Ishmael.

After flocking to Mount Arafat on Monday for prayers and reflection, pilgrims travelled on to nearby Muzdalifa to collect stones and to stay the night.

Early Tuesday they continued to Mina in groups, with leaders carrying their countries' flags and banners.

The stoning of the devil used to mark the most dangerous phase of haj for Saudi authorities as it was marred by deadly stampedes in the past as well as fires in tent camps.

In past years, however, tents have been fire-proofed while gas canisters and cooking are banned in the camps. The stoning area has been expanded to avoid overcrowding.

Saudi Arabia this year slashed the numbers of pilgrims from abroad by 21 percent and reduced the number of permits for domestic pilgrims by more than half.

The kingdom cut the quotas over fears of infections from the MERS respiratory virus and because of massive projects to expand the capacity of the Grand Mosque in Mecca, Islam's holiest place of worship.