The Canadian government is being urged to intervene following the arrest of an Edmonton imam in Saudi Arabia, who witnesses say was attacked by a mob and beaten while taking part in the Islamic pilgrimage to Mecca, the hajj.

It's believed Usama Al-Atar, who has a PhD in chemistry and is a post-doctoral fellow at the University of Alberta, has been charged with assault. However, Saudi police have not confirmed it.

Witnesses say Usama Al-Atar was beaten and kicked by men summoned by Saudi religious police before his arrest.

The attack, which took place at a cemetery in Medina early Sunday morning, was reportedly sparked when religious police approached an international group of pilgrims that included the imam.

Witnesses said angry words were spoken, then things calmed down. That's when a member of the religious police approached Al-Atar, offered to shake his hand and then called out to a group of men at a taxi stand.

They rushed in and began beating Al-Atar, kicking him and attempting to throttle him, the witnesses said.

Medina central police arrived, escorted the Canadian to a car and drove away, according to the witnesses.

Several witnesses said the attack was unprovoked, CBC journalist Muhammad Lila reported on his Twitter page.

Foreign Affairs aware of arrest

More than 200 people attended a session Sunday afternoon at the Islamic Shia Ithna-Asheri Association of Edmonton to pray for Al-Atar's safe return. Many said they wanted the Canadian government to intervene.

The Foreign Affairs Department issued a statement Sunday afternoon saying it was aware of Al-Atar's arrest and would provide consular assistance.

As well, the Islamic Human Rights Commission issued a statement Sunday calling for Al-Atar's immediate release. The U.K.-based commission, which says it campaigns for justice for people of all faiths, is trying to secure a lawyer for Al-Atar.

It's not clear whether others in the group of pilgrims with Al-Atar, including Canadians and Britons, were injured.

The annual Muslim pilgrimage, known as hajj, is a pillar of the Islamic faith and draws millions of participants to Saudi Arabia. The main sites are in Mecca, but some pilgrims travel to Medina as well.