TONGI, Bangladesh (AP) - Tens of thousands of Muslim devotees arrived Friday for the start of a three-day Islamic congregation aimed at reviving the Islamic tenets of peace and harmony.

Up to half a million devotees, many chanting verses from the Islamic holy book, the Quran, gathered for prayer on the banks of the River Turag just outside the capital, Dhaka, the area’s police chief Abdul Baten said.

More than 3 million devotees are expected to attend the World Congregation of Muslims, or Biswa Ijtema, to join a mass prayer on its final day Sunday. About 87 percent of Bangladesh’s 150 million people are Muslim.

Though most attendees are Bangladeshis, organizers say this year up to 10,000 devotees are expected from 152 other countries, including the United States.

The gathering is held every year since 1966 and aims to revive the tenets of Islam and promote peace through prayer, discussions of the Quran and sermons by Islamic scholars from around the world.

"We come here to reaffirm that Islam is a religion of peace and love," said Abdul Quddus, a 60-year-old farmer. "Islam shuns the path of violence."

More than 10,000 security personnel have been deployed to guard the congregation, one of the largest Muslim gatherings in the world, said Hasan Mahmud Khandaker, director general of the elite force Rapid Action Battalion.

Devotees arrived by buses, trains, and boats at a 190-acre (77-hectare) riverside site in the industrial town of Tongi, north of Dhaka, Baten said.

In a message Thursday, Prime Minister Sheikh Hasina greeted the devotees and said the gathering would contribute to the spread of peace.

"I think Biswa Ijtema has been significantly contributing to the spread of the essence of Islam such as universal peace, fraternity, honesty and generosity," she said.

Discussion of politics are avoided at the event and past gatherings, with as many as 3 million people attending, have been free of violence.