London Underground terror attack: Donald Trump blasts 'loser terrorists', calls for tough action

Washington: Condemning the London terror attack, United States President Donald Trump called for a tough action on the attack and said that those responsible were 'sick and demented people'. 

"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!" the US President tweeted. 

"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!," POTUS said in an another tweet. 

"The internet is their main recruitment tool which we must cut off & use better!" he added, also giving no details.

An explosion on a London Underground train on Friday was caused by an "improvised explosive device," British police said.

Twenty-two people were injured in a bomb blast on a packed London Underground train on Friday, the National Health Service said in a statement.

Eighteen were taken by ambulance and the other four made their own way to the hospital, the NHS said, adding that the injured have been taken to four London clinics.

London Mayor Sadiq Khan said Londoners will see more police on the streets of the British capital after an explosion at a metro station, which officers said was a "terrorist incident." 

"They will see over the course of today and the next few days an enhanced police presence, not simply on the public transport network but also across London," Khan told LBC Radio.