Commander Dean Haydon, who is leading the investigation, said: "I have not seen this tactic in the United Kingdom before where terrorists create maximum fear by strapping fake explosives to themselves".
Armed officers fired nearly 50 rounds, killing three attackers who had plowed a rented van into pedestrians on the bridge, killing three, then jumped out and stabbed Saturday night revelers in Borough Market, an area packed with bars and restaurants. Haydon continued to praise the police officers who had shot all three assailants dead at the scene.
Police are questioning seven suspects over suspected links to the attackers, Pakistani-born British citizen Khuram Butt, Moroccan Rachid Redouane, and Youssef Zaghba, an Italian national of Moroccan descent. 48 people were injured and more than 20 of them had serious injuries.
Also inside the van were office chairs and a suitcase which police say had been stacked inside the vehicle as a cover story to their families to explain why they had hired the van.
As noted by USA Today, authorities in London believe the attackers may have been planning a "siege situation" as part of their terror rampage.
The Metropolitan Police have released a chilling image of the pink ceramic kitchen knives used during the terror attack on London Bridge and Borough Market last Saturday.
"In terms of our witnesses that we've spoken to so far, out of the 300 odd people, there are about 20 different countries of origin".
He said he immediately clicked that it could be a terror attack.
The fake devices were plastic water bottles wrapped with tape, police said.
Police released additional details from its investigation; most notably, Butt tried online to rent a larger, 7.5-ton truck that could have killed more people, but his payment was declined.
Police shot the attackers dead just eight minutes after the first call from the public.
Another arrest has been made in the investigation into the London Bridge attack. But one of those animals could detonate and kill us all. They believe there will be many others who witnessed the incidents who have yet to speak to police, and are asking them to come forward.