'It is a reality I'm afraid that London, New York, other major cities around the world have got to be prepared for these sorts of things.
'That means being vigilant, having a police force that is in touch with communities, it means the security services being ready, but also it means exchanging ideas and best practice.'He added:
"I've had a sleepless night thinking about all of this (the New York bomb explosion) and I'm sure the Mayor has as well."
Mr Khan criticised US presidential candidate Donald Trump - who said within minutes of the attack it was time to "get tough" - for speculating on the motives behind the attack
"I'm not going to speculate as to who is responsible or how the police in New York should react. Speculating when you don't know the facts is unwise,"
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