Two of the three attackers involved in the attack on London Bridge and Borough Market on Saturday night have been identified by Metropolitan Police.
While formal identification has yet to take place, detectives believe Khuram Shazad Butt and Rachid Redouane, both from Barking, east London, were involved in the attacks.
All three attackers were confronted and shot dead by armed officers within eight minutes of being called, police noted.
The 12 people arrested on Sunday in connection with the investigation have been released without charge, police said today.
Earlier today, British Prime Minister Theresa May called for a "much more robust approach to dealing with extremism" after Saturday's terrorist attack in London that killed seven people and injured dozens more.
The prime minister made the remarks in response to questions from reporters after a campaign speech in central London.
May hailed police actions in response to Saturday's attacks, which she said "saved countless lives," but said, "We have seen overall too much tolerance of extremism in this country," and repeated her call for a commission to take up "the necessary task of stamping out extremism."
May held an emergency meeting earlier today to organize the government’s response to the attack, the third deadly terrorist event to hit the U.K. in less than three months.
Attacker was featured in a documentary about jihadists
Neighbors have identified one of the attackers as a man known as Khuram Shazad Butt, who was featured in a 2016 documentary on the British Channel 4 called “The Jihadist Next Door,” ABC News reported this morning.
Butt was part of a small group of men who openly preached for the need for Sharia law, a group that was closely monitored by authorities.
3 deadly terror attacks in under 3 months
Saturday’s deadly attack marked Britain’s third such incident since March.
It comes in the wake of a suicide bombing outside an Ariana Grande concert in Manchester May 22 that killed 22.
A separate vehicle-ramming attack in March on Westminster Bridge left four dead, including the suspect.
London Bridge partially reopens as injured victims struggle to recover
In a sign that life in the city was slowly returning to its normal routines, the London Bridge partially reopened to traffic today. The bridge had been closed since police shut it down in the midst of the attack on Saturday.
More than 30 victims remained hospitalized as of Sunday, with 21 of them in critical condition, police said. Some of those injured are foreign nationals, according to authorities. Forty-eight people were injured in total.
The French embassy in London announced, "We are very sad to report the death of one French citizen in the London attack," adding that seven more "compatriots" were in the hospital, four of whom were in serious condition, with one additional person missing.
The nearby London Bridge rail station also reopened after police cordons around it “were lifted earlier than expected,” according to transportation officials, but police said the public should expect to see extra officers on duty during Monday’s commute.
ABC News' Matt Foster, Joshuah Hoyos, Brian Ross, Rhonda Schwartz, Alex Hosenball and Seni Tienabeso contributed to this report.