Five police officers were taken to hospital today after being mauled by a dog during a raid.
The constables were attacked by a "pit bull-type" animal as they attempted to arrest a suspect in east London, Scotland Yard said.
A dog unit and firearms officer were called before the dog was "contained and subsequently shot dead", the force added.
The man - in his 20s - was arrested and is in custody.
Four of the officers were described as being in a serious but stable condition. The remaining Pc suffered minor injuries.
A force statement said: "Police attended an address in Albert Square to execute an arrest warrant at approximately 9am... While officers from Newham attempted to arrest a male suspect, they were attacked by a pit bull-type dog.
"A dog unit was called to the scene and CO19 Specialist Firearms Command also attended. The dog was contained and subsequently shot dead."
Pools of blood were visible near the entrance to the property in Albert Square.
Several officers suffered bites to their legs and arms.
The most seriously hurt officer could be facing skin grafts to repair wounds to his arms and legs.
Officers confirmed the swoop was part of Operation Big Wing, a major Scotland Yard purge on offences ranging from robbery and burglary to domestic violence.
The man, who is thought to own the dog, was arrested for grievous bodily harm and kidnapping, a spokeswoman said.
Dog bite incidents in the UK have risen 79% in London and 43% nationally in recent years, according to figures obtained by the Kennel Club.
