Muslims begin annual Hajj in sweltering heat against backdrop of war concerns

A Muslim pilgrim splashes water over his head to cool down outside the Grand Mosque (Altaf Qadri/AP)

The annual Hajj pilgrimage, one of the Five Pillars of Islam, officially began on Monday.

More than 1.5 million pilgrims have arrived in Saudi Arabia from outside the country, Saleh bin Saad Al-Murabba, commander of the Hajj passport forces, said on Friday.