Bangs and gunshots have been reported as two more addresses in east London were searched by police in connection with Saturday's deadly terror attack in the capital.
The Metropolitan Police said officers entered properties in Newham and Barking and "a number" of people had been detained and spoken to.
Residents reported hearing "loud flash bangs and gunshots" in the early hours of Monday morning.
Twitter user BatemanLDN said: "It woke me up along with the whole street. Extremely loud bangs followed by gunshot bangs.
"All ok - very shaken residents nearby though. All quietened down now."
Simon Tucker wrote: "Heard this in the Dagenham area at around 4:15 am. Started with loud explosion sound. Followed by about 20 shots, Some sounded distant."
Terrorists brought carnage to the streets of Britain for the second time in as many weeks, killing seven and leaving 21 fighting for their lives.
Pedestrians were mowed down by a van on London Bridge before attackers stabbed a police officer and revellers around Borough Market with 12-inch knives.
One of the attackers shouted "this is for Allah" as he knifed a man near a pub - while the Islamic State terror group is claiming responsibility for the attack.
Metropolitan Police Commissioner Cressida Dick confirmed police knew the identity of all three killers and Scotland Yard says it will release the terrorists' names "as soon as operationally possible".
The Commissioner said it was a "high priority" for officers to understand whether they had help from anyone else in the planning of the attack.
The three men, wearing fake suicide bomb vests, were shot dead by eight officers outside a pub after police opened fire with an "unprecedented" hail of 50 bullets, while a bystander was also shot.
Scotland Yard said seven women and five men aged between 19 and 60 were arrested under the Terrorism Act in Barking on Sunday. A 55-year-old man was later released without charge.
A vigil will be held on Monday evening near London Bridge in honour of the victims of the attack, which took place at around 10pm, while a minute's silence will take place at 11am on Tuesday.
The first victim of the attack has been named as Canadian national Christine Archibald, who worked in a homeless shelter until she moved to Europe to be with her fiance.
Her family said in a statement: "We grieve the loss of our beautiful, loving daughter and sister. She had room in her heart for everyone and believed strongly that every person was to be valued and respected.
"She would have had no understanding of the callous cruelty that caused her death."
Network Rail said London Bridge rail and London Underground stations reopened at 5am but the rail station will be exit only.
People from around the world were caught up as hundreds cowered in pubs and restaurants, barricading themselves inside as the attackers stalked the streets.
Tales of heroism emerged in the aftermath, with one British Transport Police officer taking on the trio armed only with his baton before being stabbed in the head, face and leg.
Forty-eight people were left in hospital, 21 critically injured.
As counter-terrorism police units and security services launched a huge investigation for the third time in a matter of weeks, officers arrested a dozen people in raids on flats in Barking, east London, where residents said they believed one of the terrorists may have lived.
One neighbour said one of the attackers had recently asked him how he could hire a van.
A friend of one of the attackers also told the BBC Asian Network he had reported him to the anti-terror hotline after he began expressing increasingly radical views and justifying terror attacks, but the man said he was never arrested.
Two suspects were also detained in East Ham.
Witnesses to Saturday's attack said the terrorists deliberately drove into pedestrians on London Bridge shortly after 10pm - in the same way as Westminster Bridge attacker Khalid Masood.
Attacking people after abandoning the van, they headed to Borough Market where the pubs and restaurants were packed with Saturday night crowds, many watching the Champions League final between Juventus and Real Madrid in Cardiff.
Police vans were parked outside a property on the A13 in Dagenham in east London.
James Bateman, who lives at the other side of the road, said: "At about 4am, after the large bang, I looked outside the window after being woken up and I saw about a dozen armed police officers going to and from an unmarked van."
He said they were wearing "full gear", adding: "The first bang was nothing like I'd heard before."
Mr Bateman said the bangs that followed were not as loud but sounded "the equivalent" of gunshots.
He said he thought it was more like a business address than a property where people live.
Officers were standing guard in front of the property, which is on a busy road.