British Prime Minister Theresa May is calling for a stronger response to Islamist extremism after three attackers rammed a van into pedestrians on London Bridge before stabbing others nearby. Seven people were killed and 48 injured in the attack on Saturday evening.The attack came five days before a parliamentary election. It is the third to hit Britain in less than three months. May says Thursday’s vote will go ahead.What else did May say?“It is time to say enough is enough.”“We cannot and must not pretend that things can continue as they are,” May continued. She called for a beefed-up counter-terrorism strategy that could include longer jail sentences for some offences and agreements to regulate cyberspace.“We believe we are experiencing a new trend in the threat we face as terrorism breeds terrorism.”“Perpetrators are inspired to attack not only on the basis of carefully constructed plots… and not even as lone attackers radicalised online, but by copying one another and often using the crudest of means of attack.”Less than two weeks ago, a suicide bomber killed 22 children and adults at a concert by US singer Ariana Grande in Manchester in northern England. Five people died in March after a man drove into pedestrians on Westminster Bridge in central London and stabbed a police officer.May said the series of attacks is not connected in terms of planning and execution, but were inspired by what she called a “single, evil ideology of Islamist extremism” that represented a perversion of Islam and of the truth.She said this ideology had to be confronted both abroad and at home, adding that the internet and big internet companies provided the space for such extremism to breed.May, who was the UK interior minister between 2010 and 2016, said there was too much tolerance of extremism in Britain.“While we have made significant progress in recent years, there is – to be frank – far too much tolerance of extremism in our country,” she said, urging Britons to be more robust in stamping it out in the public sector and in wider society.After the Manchester attack, Britain raised its threat level to “critical” – meaning an attack is expected imminently. But this has been downgraded back to “severe” which means an attack is highly likely.Are there any details about those who died yet?Yes.A Canadian national was among those killed, Canadian Prime Minister Justin Trudeau said in a statement. None of the dead have been identified by name. French and Australian authorities said nationals from their countries were among those injured.What about the attackers?Police shot the three male attackers dead in the Borough Market area near London Bridge within eight minutes of receiving the first emergency call shortly after 10pm local time.Mark Rowley, the head of counter-terrorism police, said eight officers had fired around 50 bullets to stop the attackers.“The situation these officers were confronted with was critical, a matter of life and death. Three armed men, wearing what appeared to be suicide belts, had already attacked and killed members of the public and had to be stopped immediately,” Rowley said.A member of the public received non-critical gunshot wounds during the incident, Rowley added.What about the arrests?Police in London arrested 12 people in the Barking district in the east of the city in connection with the attack. Raids are continuing in the area.“This is for Allah!”Eyewitnesses have described harrowing scenes. The attackers’ white van veered on and off the pavement, hitting people along the way. The three men ran into an area at Borough Market packed with bars and restaurants, stabbing people indiscriminately.Some people tried to barricade themselves into a pub while others tried throwing tables and other objects to fend off the attackers.Health officials said on Sunday that 36 of those injured remain in hospital. 21 are in a critical condition.The government has announced that a nationwide minute of silence would be held at 1000 GMT on Tuesday to pay respect to the victims of the attack. Flags will remain at half-mast on government buildings until Tuesday evening.Has anyone admitted being behind the attack?Not yet. There was no immediate claim of responsibility for the London Bridge attack.ISIL had sent out a call on the instant messaging service Telegram early on Saturday urging its followers to carry out attacks with trucks, knives and guns against “Crusaders” during the Muslim holy month of Ramadan.Islamist militants have carried out scores of deadly attacks in Europe, the Middle East, Africa, Asia and the US over the past two years.