LONDON - Police raided a building in east London that was the home address of one of the three attackers who killed seven people in the city centre, Sky News reported on Sunday (June 4), citing unnamed sources.

Police said they were looking into media reports linking the raid to a Saturday night attack in which three people drove a van into pedestrians on London Bridge before stabbing revellers nearby. Police did not confirm the two incidents were related.

The raid is believed to have started at around 7am local time, hours after the attack targeting the London Bridge and Borough Market. Sky News reported that four men and one woman had been detained during the raid. The speed at which the raid was ordered could indicate that authorities may know the identity of at least one of the attackers, according to the Sunday Express.

A Reuters witness described a heavy police presence and a cordon around a block of flats as residents of other flats in the building looked out from their windows onto the scene. An eyewitness to the raid told Sky he heard several bangs during the operation and was later told they were controlled explosions used to gain access to the building.

Sky News showed aerial footage of a cordon around a block of flats and an ambulance parked outside the address.

There was no police statement immediately available, and it was unclear if there was any link to an attack in London which killed seven people on Saturday night, Reuters reported.

Further raids are allegedly being carried out elsewhere in Billericay, Essex, north-east of London.