The pilgrims started their way for Mina by road, by train or on foot on Sunday in a bid to pray and rest before moving on to Mount Arafat on Monday for the climax of the pilgrimage rituals.
The men are required to wear the seamless two-piece garment and the women should cover up themselves, except faces and hands.
More than 100,000 troops have been deployed to Mecca to ensure the safety of the pilgrims.
Saudi Interior Minister Prince Mohammed bin Nayef said the number of pilgrims from outside the country totalled 1,379,531 million, down 21 percent on last year’s 1.75 million.
Around 1.29 million of them had flown to Saudi Arabia from 188 countries, he said, without giving a figure for pilgrims residing in the kingdom whose number is believed to have been halved.
The kingdom cut by 20 percent the quotas for pilgrims allowed in from abroad over fears of MERS and because of massive projects to expand the capacity of the Grand Mosque, Islam’s holiest place of worship.
All the pilgrims who enter Mecca should undertake a minor Hajj before performing their major Hajj, which began on October 13.
The major Hajj is performed during a five-day period from the 8th through the 12th of Dhu al-Hijjah, the last month of the Muslim lunar calendar.
The Hajj pilgrimage is obligatory for all Muslims once in their lifetime if they are able both physically and financially. The teachings of Hajj are also very significant. Muslims remember that they are not joined together on the basis of color or race, but on the basis of belief in God and His messenger.
Saudi Health Minister Abdullah al-Rabia told reporters late Saturday the authorities had so far detected no cases among the pilgrims of the MERS virus which has killed 60 people worldwide, 51 of them in Saudi Arabia.
The hajj is one of the five pillars of Islam that every capable Muslim must perform at least once.