Protesters have gathered outside a police station in north-west London following the arrest of teenage boy.
About 40 people assembled outside of Colindale Police Station in Barnet.
It comes after a 14-year-old was arrested on suspicion of possession of cannabis earlier. Police said they were obstructed from making the arrest.
A 19-year-old has also been arrested for allegedly assaulting an officer. A dispersal order has been issued and a cordon is in place around the station.
A number of officers suffered minor injuries but did not require treatment and more officers are supporting the dispersal of the group near the police station, the Met Police said.
In a statement Scotland Yard said: “We have not received any reports that members of the public or those under arrest sustained any injuries.”
Officers arrested the 14-year-old near Grahame Park at about 14:40 BST.
As they were doing so, a group began to gather around officers and “obstructed the police vehicle from leaving the scene”, the Met said.
Two men, aged 23 and 25, were arrested on suspicion of obstruction of a police constable.
The police vehicle left the scene and a group of 30 to 40 followed on foot to the police station, the Met added.
All of those arrested remain in police custody.