Some 12 people have been arrested at multiple addresses in Barking, east London Sunday morning following armed raids by British counter terrorism police. Searches at the locations are ongoing.

The investigation into Saturday’s terrorist attack at London Bridge and Borough Market is “progressing rapidly” according to a statement from Scotland Yard.

British Prime Minister Theresa May called an emergency meeting of top security officials Sunday morning and has been briefed about the ongoing investigation.

Enough is enough. Read my response to last night’s brutal terror attack: https://t.co/MHQ4SPG0aQ — Theresa May (@theresa_may) June 4, 2017

“This is, as we all know, the third terrorist attack Britain has experienced in the last 3 months. In March, a similar attack took place, just around the corner on Westminster Bridge,” May said in a statement published on Facebook.

“Seven people have died as a result of the attack, in addition to the 3 suspects shot dead by the police. Forty-eight people are being treated in several hospitals across London. Many have life-threatening conditions," she added.

READ MORE: 3 attackers shot dead after killing 7, injuring at least 48 in London Bridge terrorist attack Live updates

May also confirmed that British Intelligence and police have disrupted five credible terrorist plots since the Westminster attack in March.

She also stated that the recent attacks are not directly connected but are instead part of a new emerging trend in global terrorism with copycat attackers employing “the crudest means of attack” as opposed to “carefully-constructed plots after years of planning and training.”

She also decried the lackluster response to the threat posed by such terrorist acts, citing “far too much tolerance of extremism” in the UK.

“But it is time to say enough is enough... But when it comes to taking on extremism and terrorism, things need to change,” May concluded.

"This is a fast-moving investigation and we have significant resources deployed both to the investigation and to the visible patrols that people will be seeing as they wake up this morning. We will have increased patrols in many areas by the police, and these will as you would expect include armed officers,” Metropolitan Police Commissioner, Cressida Dick, said in a statement earlier on Sunday.