President Trump called for a “larger, tougher” travel ban early Friday after the attack in London, calling the perpetrator a “loser” and saying the U.S. will have to get “nasty” to fight terrorism.

“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 president tweeted Friday morning.

Moments later, he added: “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!”

The president’s tweets come after a fire at a London subway station on Friday, which sent at least 22 people to hospitals. London’s Metropolitan Police said the fire has been declared a “terrorist incident.” Police said it was caused by the detonation of an improvised explosive device.

According to the White House, Trump later spoke with British Prime Minister Theresa May to “convey his sympathies and prayers” for those injured.

“The President pledged to continue close collaboration with the United Kingdom to stop attacks worldwide targeting innocent civilians and to combat extremism,” the White House said in a statement.

Trump told reporters Friday morning, "We have to be very smart. We have to be very, very tough."

In an early morning tweetstorm, Trump slammed political correctness, as he once again made the case for his travel ban which continues to be fought out in the courts.

“The travel ban into the United States should be far larger, tougher and more specific-but stupidly, that would not be politically correct!” Trump tweeted, adding, “We have made more progress in the last nine months against ISIS than the Obama Administration has made in 8 years. Must be proactive & nasty!”

Trump has been outspoken about the terror threat in London, urging the public to “stop being politically correct and get down to the business of security of our people” after the attack by the London Bridge in June, which killed seven and injured dozens.

“My thoughts are with those injured at Parsons Green and emergency services who are responding bravely to this incident,” British Prime Minister May said Friday.

However, former chief of staff to May Nick Timothy on Friday called Trump's "loser terrorist" tweets “unhelpful.”

“True or not—and I’m sure he doesn’t know—this is so unhelpful from leader of our ally and intelligence partner,” Timothy tweeted Friday.

The Associated Press contributed to this report.