Activists linked to the U.S.-based group Black Lives Matter blocked a road Friday leading to London's Heathrow Airport and held protests in other British cities.

London's Metropolitan Police said officers arrested 10 people blocking a road leading from a main highway to Heathrow on Friday morning, including six who were "locked" to one another.

The protesters said they were marking the fifth anniversary of the death of Mark Duggan, a 29-year-old black man shot by London police under disputed circumstances on Aug. 4, 2011.

The killing sparked Britain's worst civil disorder in decades, several nights of rioting that spread from London to cities around the country.

Wail Qasim, who was at the Heathrow protest, told ITV News: "Since 1990, at least, we've seen zero convictions for over 1,563 deaths in police custody."

The protests have been organised for the day after the anniversary of Mark Duggan's death, which sparked riots nationwide in the summer of 2011.

Footage showed police dragging protesters out of the road in a bid to ease congestion.

Watford Town Centre Police on Riot Night following death of Mark Duggan