LONDON (AFP) - Five people have been arrested in London after videos emerged online of a group of men abusing passers-by for being gay, drinking alcohol or wearing mini-skirts in what they said was a "Muslim area", police said today.

The arrests were made over what Scotland Yard described as "filmed harassments" in east London, an area with a high concentration of Muslims, earlier this month.

Detectives voiced particular concern about a YouTube video entitled "Muslim vigilantes in London harass and taunt gay male", in which a group of men verbally abuse a man in the street for being homosexual.

"Don't you know this is a Muslim area?" an off-camera voice in the video says. "You need to get out of here... You're dirty, mate. You're gay mate, get out of here..."

Detective Chief Inspector Wendy Morgan urged the victim to come forward, saying the police "takes such homophobic behaviour very seriously".

"This man is a crucial witness in the investigation and would encourage him and anyone else with information relating to this incident to make contact in confidence as soon as possible," she said.

Another video posted on YouTube, entitled "Muslims enforcing Sharia Law on the streets of London" and dated January 2013, shows other people being harassed.

It shows a group of men asking a woman in a mini-skirt to "not dress like this in a Muslim area". The girl says she is "appalled", adding: "This is Great Britain." But the man says: "It's not so Great Britain." The men also ask revellers out on a Saturday night to move away from their mosque, and demand that one man put down his beer, saying: "No drink in this area... this is a Muslim patrol. Alcohol is evil." Five men aged between 17 and 29 years old have been arrested since Sunday, all on suspicion of grievous bodily harm and public order offences.

One was held in Acton, west London, and the others in east London, police said.