Riyadh, Jun 14 (IANS/DPA): Muslims from around the world started the Haj pilgrimage in Saudi Arabia on Friday, with authorities expecting 2 million people to gather this year amid sweltering heat.

After circling the Kaaba, a stone cube-shaped holy building inside the Grand Mosque in Mecca, pilgrims head to the nearby Mina Valley, where they will spend the night in a massive tent city.

On the second day, they head to Mount Arafat, around 20 kilometres east of Mecca, where they stay until sunset in what is considered the peak of the Hajj pilgrimage.

As the temperature in and around Mecca is expected to reach 43 degrees Celsius, authorities urged pilgrims to carry umbrellas to protect themselves during the rituals.

The Hajj, one of the five pillars of Islam, is a mandatory duty for all Muslims to make once in a lifetime - if they are physically capable of undertaking the journey to the birthplace of the prophet Mohammed and have the financial resources.

Men wear seamless white clothes, and women wear loose garments as they perform the same rituals in a demonstration of religious unity, equality and pursuit of spiritual renewal.

The pilgrimage takes place from the eighth to the 12th day of Dhu al-Hijjah, the last month of the Islamic lunar calendar.