A spokesman for Mr Khan later branded Mr Trump's comment "ill-informed" and said the president had deliberately taken out of context remarks made by the mayor to reassure people about the increased police presence in the wake of the attack.
A police officer armed only with a baton along with a chef wielding a bread basket were among heroes emerging Sunday after a London terror attack that killed seven people and wounded almost 50 others.
A member of the public was accidentally shot and remains in hospital in a non-critical condition, Assistant Commissioner Mark Rowley said. "When it comes to taking on extremism and terrorism, things need to change". The police were on the scene within two minutes of the attack, sources said. British counter-terrorism police said they had arrested 12 people in Barking, in east London, in connection with the van and knife attack.
Police fired 50 bullets at three men who launched an attack on London Bridge on Saturday night, and one member of the pubic was caught in the crossfire.
Most political parties have suspended national general election campaigning, but the prime minister said full campaigning would resume on Monday.
"We cannot and must not pretend that things can continue as they are".
The backlash was intense on social media, where commentators said that Uber should have immediately disabled surge pricing for people trying to make their way home across the capital.
One of those officers confronted one of the attackers with a baton.
Britain's official terrorism threat level was raised from "severe" to "critical" after the Manchester attack, meaning an attack may be imminent.
Some Londoners attempted to fend off the knifemen by throwing chairs, glasses and bottles at them as they attempted to attack people in restaurants and bars.More news: Bumbling Trump Proves Gun Control Argument With Post-London Attack Tweet
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He said he came upon the attackers and "hit one of them in the head with a basket and I knocked him out", Morariu told British TV.
The UK PM said attacks are now inspired "by copying one another and often using the crudest of means of attack".
A taxi driver told the BBC that three men got out of the van with long knives and "went randomly along Borough High Street stabbing people".
Police officers yelled at people to run from the area, and blasts were heard as officers performed a series of controlled explosions.
Ms Grande returned to Manchester on Sunday night to perform in a benefit concert for victims.
"It was really scary", he said. Law enforcement officials in major USA cities said they were not aware of any threats but were on alert.
Last month U.S. President Donald Trump urged Arab and Islamic leaders to unite and do their share to defeat Islamist extremists, making an impassioned plea to "drive out" terrorists, while toning down his own harsh rhetoric about Muslims.
Italian photographer Gabriele Sciotto, who was watching the European Champnions League football final at the Wheatsheaf pub in Borough Market, said he saw three men shot just outside the premises.
Neighbors at the site of one raid in Barking said a man who lived there resembled one of the attackers shown in news photographs.
In March, five people died after an attacker drove a auto at pedestrians on Westminster Bridge and stabbed a policeman in the grounds of parliament.