Nearly 3 million Muslims from around the world, chanting "I am here, Lord" and raising their hands to heaven, marched through a desert valley outside Mecca on Thursday in the first day of the annual hajj pilgrimage. This year's hajj takes place amid increasing worries across the Islamic world - over the bloodshed in Iraq, violence in the Palestinian territories and a new war in Somalia. Amid the crises, tensions have increased between the two main sects of Islam, Sunnis and Shi'ites, who come together in the five days of hajj rituals centered around the holy city of Mecca, birthplace of Islam's Prophet Muhammad. "We will not allow sectarian tensions from any party during the hajj season," Saudi Arabia's Interior Minister Prince Nayef bin Abdulaziz told reporters ahead of the rituals. "The pilgrimage is not a place for raising political banners ... or slogans that divide Muslims, whom God has ordered to be unified," Saudi Islamic Affairs Minister Sheik Salih bin Abdulaziz told pilgrims Thursday. "The hajj is a school for teaching unity, mercy and cooperation."