WATCH: #YouAintNoMuslimBruv Trending on Twitter After London Stabbing

The hashtag began to trend as video emerged of passersby appearing to yell 'you ain't no Muslim, bruv' at the alleged attacker as he was pinned down by police.

Image from #YouAintNoMuslimBruv Twitter hashtag
Screen grab

After a knife-wielding attacker stabbed three people while screaming "this is for Syria", in what police described as a terrorist incident, a Twitter hashtag, #YouAintNoMuslimBruv, often appearing with video and photos of the scene began trending on Twitter Sunday.

The hashtag began to trend as video emerged of passersby appearing to yell 'you ain't no Muslim, bruv' at the alleged attacker as he was pinned down by police. 

Police officers investigate a crime scene at Leytonstone underground station in east London, Britain December 6, 2015.
Reuters

An eyewitness quoted by The Guardian and other British newspapers said the attacker appeared to claim that he was retaliating for Western air strikes on Islamist militants in Syria. Police declined to comment on those reports and it was not immediately possible to verify them independently. 

British war planes joined the first bombed on targets in Syria for the first time on Thursday, a few hours after parliament had approved the involvement.