YouTube says it has deleted more than half of the "violent" music videos that the country's most senior police officer asked it to take down.

More than 30 clips have been removed so far.

Metropolitan Police Commissioner Cressida Dick has blamed some videos for fueling a surge in murders and violent crime in London and singled out drill music.

She asked YouTube to delete content which glamorizes violence.

Drill music originated in Chicago. Its biggest breakout star is arguably Chief Keef, famous for his 2012 track I Don't Like.

The genre's lyrics often detail vivid accounts of taking drugs and violence.

In February, 17-year-old rapper Junior Simpson was sentenced to life in prison after he and three others stabbed 15-year-old Jermaine Goupall to death.

The court heard he'd penned a track about knife attacks before carrying out the killing.