"Officers have made 12 arrests and are at present searching 4 properties… 55-year-old man arrested at address 2 in Barking, who has since been released without charge," Rowley said as quoted in a police statement.
On Saturday, at 22:08 local time (21:08 GMT), a vehicle struck pedestrians on London Bridge. The vehicle with three suspects continued to drive from London Bridge to Borough Market, after which the suspects left the vehicle and carried out a stabbing attack at the market. The attackers were confronted by the police and shot dead within minutes.
According to the local authorities, at least seven people were killed and 48 more injured.