The Metropolitan police has singled out drill music.

YouTube has deleted more than 30 videos following complaints from the Metropolitan police that they appear to glamorize violence.

As the BBC reports, Metropolitan Police Commissioner Cressida Dick has singled out drill music, allegedly linking the increase in violent crime in London to the rap genre, which often features violent imagery and lyrics.

Pressplay, a music company that promotes drill videos, wrote on Instagram that police had “forced” YouTube to take some clips down because of “what’s happened lately.” Scotland Yard has compiled a database of more than 1,400 videos to use as an intelligence tool.

“The gangs try to outrival each other with the filming and content – what looks like a music video can actually contain explicit language with gangs threatening each other,” said the Met Police’s Mike West. West also said that the number of videos that “incite violence” have been increasing since late 2015.

Earlier this year, 17-year-old London rapper Junior Simpson was given a life sentence for the murder of teenager Jermaine Goupall in south London. Simpson had previously written a song about knife violence.

A YouTube spokesman said: “We have developed policies specifically to help tackle videos related to knife crime in the UK and are continuing to work constructively with experts on this issue.

“Along with others in the UK, we share the deep concern about this issue and do not want our platform used to incite violence.”

A petition has been launched by drill group 1011, with over 5,000 people so far demanding that YouTube stop targeting the genre.

Read next: From Chicago to Brixton: The surprising rise of UK drill