(AP) -- Decisive action is needed to prevent sectarian tensions from escalating in Egypt, the country's top Islamic leader said Tuesday in the wake of a fatal riot fanned by Muslim protests over a DVD deemed offensive to their faith.

The comments by Grand Imam Mohammed Sayyed Tantawi come after four people were killed when a crowd of 5,000 Muslims rioted Friday in a Christian neighborhood in Egypt's second-largest city of Alexandria.

"We should take quick action to bridge the chasm as soon as we hear about a conflict erupting between Muslims and Christians," Tantawi, quoting a famous Arabic poem, said on the sidelines of the opening of a six-day gathering of Anglican clerics from around the world being held in the Egyptian capital, Cairo.

Tantawi, Pope Shenouda III of the Coptic Orthodox Church and the Egyptian government failed to contain Muslim anger over a play performed two years ago by a Christian church in the port city of Alexandria and circulated recently on a DVD.

Tantawi heads the prestigious al-Azhar University, the world's highest seat of learning for Sunni Muslims.

The play, entitled "I Was Blind But Now I Can See," angered Muslims as it tells the story of a young Christian who converts to Islam and becomes disillusioned.

Some believed the DVDs were circulated to spark protests by Muslims in Alexandria against a Coptic Christian man who had been nominated by Egypt's ruling National Democratic Party to stand in next month's parliamentary elections.

Tantawi addressed some 120 conservative delegates - including clerics from Anglican churches in Africa, Asia and Latin America - who are taking part in a conference expected to tackle divisive issues such as gay clergy and same-sex unions.

Such issues have threatened to break apart the world's 77 million-member Anglican communion, with conservative Anglicans warning they could form independent, breakaway churches.

The tensions have become so alarming that the leader of the Anglican communion, Archbishop of Canterbury Rowan Williams, plans to travel to Egypt in an apparent attempt to calm dissent led by powerful Nigerian Archbishop Peter Akinola.

The conference is expected to continue Wednesday in the Red Sea resort of Ain el-Sukhnna and tackle various key issues, which include preventing wars, diseases and poverty.

By Maggie Michael