MECCA, Saudi Arabia, Nov. 25 (UPI) -- The hajj, one of the biggest religious pilgrimages each year, begins Wednesday with an estimated 2.5 million Muslims heading to Mecca in Saudi Arabia.
Muslims who are physically able are expected to travel to Mecca at least once to fulfill the fifth pillar of Islam. This year the convergence of Muslims on Mecca occurs through Sunday.
The sheer number of people causes logistical and other problems in Saudi Arabia but this year there's another concern. With millions of people mingling closely together, the fear of the spread of the H1N1 flu virus has led authorities to have 20,000 medical staff on hand in addition to 100,000 security personnel.
Violence is also a concern for Saudi authorities after Iranian leaders said the hajj should be used for demonstrations against the United States and Israel. It is unclear how much of that will happen but the call could feed the usual tensions as Sunni and Shiite Muslims, sects often at odds with each other, come together.
The flu, however, is a present threat. About two dozen early arriving pilgrims became sick with swine flu and four, who had additional health issues, died. The Saudis opened six clinics at the Grand Mosque and have 1.5 million doses of Tamiflu on hand to fight a flu outbreak.