British police said on Monday they had charged seven people with violent disorder - one of them additionally with racially aggravated grievous bodily harm - in connection with what is being treated as a "hate crime" that targeted a young asylum seeker.

According to an earlier police statement, a 17-year-old Kurdish-Iranian boy was waiting for a bus in the London borough of Croydon with two friends just before midnight on Friday. They were approached by a group of people who asked where he was from, and upon ascertaining he was an asylum seeker, "chased him and launched a brutal attack," the statement read.

"He sustained serious head and facial injuries as a result of this attack, which included repeated blows to the head by a large group of attackers," said Detective Sergeant Kris Blamires in the statement.

London's mayor, Sadiq Khan, has said those who had carried out the attack would be "brought to justice."

'Confidence in numbers'

Police now say there may have been as many as 30 people involved.

"I think this was probably confidence by numbers," said Detective Superintendent Jane Corrigan. "It started off with this smaller group of people, who were joined by between 20 to 30, and they just viciously attacked these individuals because they were asylum seekers."

The boy is in hospital with a fractured skull and a blood clot on the brain, but police say he is starting to make a recovery. Police are trying to find his family, who live in Iran.

The seven charged so far are aged between 17 and 24 and all live near where the assault took place.

Immigration has long been a contentious issue in Britain, and dissatisfaction with the way the EU handles the issue was a major factor in swaying voters to leave the bloc in last year's Brexit referendum. Since the referendum, hate crimes targeting nationals from other countries have spiked.

Last year, 62,518 hate crimes were recorded by police in England and Wales, compared with 52,465 the year before - an increase of 19 percent.

mz, tj/msh (Reuters, AP)