United States President Donald Trump on Friday called the terrorist incident in London as another attack 'by a loser terrorist' prompting British Prime Minister Theresa May to rebuke him by asking not to 'speculate'.
Trump said that he has been briefed on London attack and would soon be speaking to the British prime minister.
Later, the White House said that Trump called the British PM and pledged to continue 'close collaboration' with the United Kingdom to stop attacks worldwide.
During the telephone call, Trump conveyed his sympathies and prayers for those injured in the attack, the White House said in a statement.
'The president pledged to continue close collaboration with the United Kingdom to stop attacks worldwide targeting innocent civilians and to combat extremism,' it said.
Earlier, Trump in a brief interaction with reporters described the attack as a terrible thing.
"It's a terrible thing. It keeps going and going, and we have to be very smart and we have to be very, very tough -- perhaps we're not nearly tough enough," Trump told reporters in the Rose Garden of the White House.
'Another attack in London by a loser terrorist. These are sick and demented people who were in the sights of Scotland Yard. Must be proactive,' Trump said in a series of tweets.
'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 said in another tweet.
But May dismissed the speculative tweet from Trump that claimed Scotland Yard had the so-called 'bucket bomber' in terror attack on a London Underground train in their 'sights'.
"I never think it's helpful for anybody to speculate on what is an ongoing investigation," May said.
"As I have said the police and security services are working to discover the full circumstances of this cowardly attack and to identify all those responsible," she said.
Scotland Yard also dismissed the Trump's claims.
A spokesperson for the Metropolitan Police said the US President's comments, which did not correspond with any information released by the UK authorities, were 'unhelpful'.
The British Prime Minister, who described the attack involving an improvised explosive device on a Tube train at Parsons Green station as a 'cowardly' act 'clearly intended to cause significant harm', was addressing the media after chairing an emergency response COBRA committee meeting at Downing Street.
An IED went off on an underground train during the morning rush hour at a busy station in London, leaving at least 22 people injured, in what Scotland Yard called a 'terrorist incident'.
'The travel ban into the US should be far larger, tougher and more specific-but stupidly, that would not be politically correct!' Trump said.
When asked what he meant about the Muslim ban has to be more specific, Trump said "we have to be smarter".
'We have made more progress in the last nine months against the ISIS than the Obama administration has made in eight years. Must be proactive and nasty!' the US president said in another tweet.
In a statement, Congressman Robert Pittenger said this vicious terrorist attack on innocent commuters in London with an improvised explosive device once again reflects the harsh reality of these barbaric adversaries.
"We must be vigilant and united in our efforts to expunge these diabolical enemies," said Pittenger, who serves as the vice chairman of the House Financial Services Subcommittee on Terrorism and Illicit Finance, and chairman of the Congressional Task Force on Terrorism.
'I am sickened by the terrorist attack in London and am praying for the victims. Our whole nation stands with our allies in the UK,' tweeted Congressman Steve Scalise.
"Praying for those injured in today's terrorist attack in London. We stand with the UK & reaffirm our commitment to combating radical terror," said Congressman Dan Donovan.
'My thoughts and prayers are with the people of London. We must take a global stand against violence and terrorism,' tweeted Congressman Yvette Clarke.
Photograph: Carlos Barria/Reuters