The Metropolitan Transportation Authority, which operates mass-transit lines in New York City and the Long Island Rail Road and Metro-North commuter lines, said it was closely monitoring the investigation of the fiery blast that injured 29 people in a West London underground station.
"We have made a significant arrest in our investigation this morning", Neil Basu, Senior National Co-ordinator for Counter Terrorism Policing, said in a statement.
President Donald Trump responded to an apparent terror attack in London on Friday by suggesting that his controversial travel ban ought to be extended.
Trump told reporters after his tweet that he had been briefed on the London incident, and he also said he would be speaking with May, although it was not clear whether his reference to Scotland Yard came up on the call.
Last year Damon Smith, a student with an interest in weapons and Islamic extremism, left a knapsack filled with explosives and ball bearings on a London subway train. He and his son Donald Trump Jr both mocked Sadiq Khan after taking the mayor's words of reassurance to Londoners out of context.
Following Friday's explosion, Trump took to Twitter to condemn the "loser terrorist" behind the attack, making assumptions that the individual was likely associated with ISIS.
May said military troops would augment the police presence in a "proportionate and sensible step".
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The Riyadh regime, he said, was looking to depose Qatari Emir Sheikh Tamim bin Hamad Al Thani. The Saudi envoy warned that Qatar would soon "regret" its orientation towards Iran.
"I think he means generally that this kind of activity is what we're trying to prevent", McMaster said.
"Loser terrorists must be dealt with in a much tougher manner.The internet is their main recruitment tool which we must cut off & use better!" he continued.
Police and health officials said 29 people were treated in London hospitals, majority for flash burns.
Khan added that he's attending an emergency COBRA security meeting with British Prime Minister Theresa May this afternoon.
He did not immediately offer condolences to the British people.
"We need to be smart, vigilant and tough". We have to see Bill Gates and a lot of different people that really understand what's happening.
The same court ruled that refugees accepted by a resettlement agency should be allowed to sidestep the White House's broad ban, opening the door for as many as 24,000 refugees to enter the country before the end of October.