Anti-terrorism police are investigating claims of sectarian violence between Shi'ite and Sunni Muslims after an Iraqi refugee was attacked in a suspected hate crime in central London.
Five men have been arrested following the attack, which took place in Edgware Road on 10 May after a rally against the Syrian regime, where radical cleric Anjem Choudary was a speaker.
SO15, the Metropolitan Police's counter-terrorism branch, has been drafted in to conduct the investigation into violent disorder and suspected grievous bodily harm.
The suspects, all aged between 18 and 38, are on bail pending further inquiries.
In a second incident at the same event a Sunni man was attacked after being mistaken for a Shi'ite, according to reports. No arrests have been made.
The conflict in Syria has divided Britain's Muslims, with significant numbers travelling to the country to take part in the opposition to the regime of Bashar al Assad..