Mecca, Saudi Arabia ? Some 2 million Muslim pilgrims massed in their holiest city Tuesday to reaffirm their faith after a tumultuous year that has raised fears Islam is being demonized after the Sept. 11 terror attacks.

The pilgrims include thousands of Afghan Muslims brought by an international airlift organized by Britain, the United Arab Emirates, Saudi Arabia and Pakistan.

Calls to prayer echoed over the city at sunset, followed by an eerie silence as hundreds of thousands or worshippers from around the world bent to offer whispered prayers around the Kaaba, Islam’s holiest shrine, in Mecca’s Grand Mosque.

The silences alternating with the deep voice of the cleric reciting from the Quran, Islam’s holy book brought a sense of peace and order to Mecca, a sleepy city that has been transformed in a matter of days into a teeming metropolis for the annual hajj, or pilgrimage.

The hajj is one of the five pillars of Islam. Every able-bodied Muslim is required to perform it at least once in a lifetime if he or she can afford it.

This year’s hajj is taking place at a time when many of the world’s 1.2 billion Muslims believe that their faith, born in Mecca 14 centuries ago, is the target of a hate campaign by the West following the Sept. 11 attacks on the United States.

Saudi-born exile Osama bin Laden and his al-Qaida terror network are blamed for the attacks, which killed thousands and sparked the U.S.-led military campaign in Afghanistan after its former Taliban rulers refused to surrender bin Laden for trial.

Fifteen Saudis were among the 19 suspected hijackers who slammed airliners into New York’s twin towers and the Pentagon in Washington on Sept. 11. A fourth plane crashed into a Pennsylvania field.

“Islam has been the victim of Sept. 11,” said Ahmad Turkistani, a Saudi who heads the Virginia-based Institute of Islamic and Arabic Studies in America.

“We need to disassociate Islam from the wrong practices of some of its followers and protect it from those who want to associate it with violence and destruction,” said Turkistani, 48, who is in Mecca for the hajj.

Because of post-Sept. 11 tensions and the war in Afghanistan, Saudi authorities have taken stringent security measures in Mecca a city of 500,000 during the rest of the year.

More than 80,000 volunteers, police and soldiers have been deployed in Mecca. The city is closed to non-Muslims during the hajj.