Police aim guns at balcony above a betting shop in East Ham. ? Twitter

LONDON: Police have raided a building in East Ham and are currently searching it, British media reported, after three men rammed a van through crowds of pedestrians on London Bridge Saturday, before attacking revellers with knives, killing seven people.

Police are searching a building in East Ham that has been cordoned off, the Independent reported. There is heavy armed police presence on Barking Road, but it is not yet confirmed whether it was linked to the earlier arrests.

Police arrest 12 over London attacks that killed 7

At least 48 people were injured in the attack, the third to hit Britain in less than three months

Images and video footage from the scene show at least half a dozen police vans parked in the High Street area, with dozens officers standing in the middle of the road.

The development comes hours after arrest of 12 people in connection with Saturday's stabbing rampage.

Sources told Sky News, the flat was home to one of the people suspected to have taken part in the stabbings, but the Metropolitan Police did not immediately comment.

Residents reported hearing loud bangs and said they were later told by police they were controlled explosions.