MECCA: Enormous crowds of pilgrims thronged Mecca, Islam's holiest city for biggest Hajj pilgrimage in years, with more than two million expected to brave scorching Saudi Arabian heat.

Pilgrims in white robes and sandals packed ancient city, now dotted with luxury hotels and air-conditioned shopping malls, after flooding in on planes, buses and trains for annual rites.

This year's Hajj one of world's biggest annual religious gatherings could break attendance records, officials said. "As Hajj draws near, Kingdom of Saudi Arabia prepares for largest Islamic gathering in history," Minister of Hajj and Umrah Tawfiq Al-Rabiah said in video published by Ministry this week.

Faithful will circle Holy Kaaba, pray on Mount Arafat and stone devil by throwing pebbles at three giant concrete walls representing Satan.

More than two million people from more than 160 countries will attend, Rabiah said dramatic increase on 926,000 from last year, when numbers were capped at one million post-endemic.

In 2019, about 2.5 million people took part. Only 10,000 were allowed in 2020, at height of Covid-19, rising to nearly 59,000 year later.

Hajj is among five pillars of Islam and must be undertaken by all Muslims with means at least once in their lives.

This Hajj will be biggest since requirement for women to be accompanied by male guardians was dropped in 2021.

This year, the maximum age limit has also been scrapped, meaning thousands of elderly will be among those contending with Saudi summer temperatures that are expected to reach 44 degrees Celsius. Hajj begins late Sunday at Grand Masjid in Mecca. Worshippers will sleep in tents on Monday night and spend Tuesday at Mount Arafat, climax of Hajj, where Holy Prophet (PBUH) delivered his final sermon. After casting pebbles in stoning of devil ritual on Wednesday, marking start of Eidul Azha holiday, pilgrims return to Mecca to perform farewell tawaf.

Mecca pilgrimages are major source of income for Saudi Arabia, which is embarking on an ambitious plan to overhaul its largely oil-dependent economy. Hajj and year-round Umrah generate an estimated $ 12 billion annually.