"Who can figure out the true meaning of "covfefe"???" he tweeted yesterday after his mystery tweet sent the Internet into meltdown.
Donald Trump criticises Sadiq Khan's response to London attack
The area remained cordoned off and patrolled by armed police and counter-terrorism officers on Sunday, with train stations closed. President Donald Trump and Vice President Mike Pence have been briefed about the situations in London , officials say.
"The Twitterverse greeted covfefe's arrival with unfettered rapture", the host said.
He blew past follow-up questions about the meaning of covfefe.
Timeline: How events unfolded in London's latest attack
Police have described the operation as "ongoing", adding that it was being led by London's Metropolitan Police force. Khan had also condemned the attacks "in the strongest possible terms" and said he was "grieving" for the victims.
One user joked that "covfefe" is already a popular name for babies in states that voted for Trump.
Trump was relatively quiet on Twitter during a nine-day trip to Middle East and Europe but resumed tweet storms after returning home on Saturday.
The White House spokesman, during a truncated off-camera briefing Wednesday, brushed aside a question about a report that fired FBI director James Comey plans to testify publicly that the president pressured him to end an investigation into a top Trump aide's ties to Russian Federation. Moreover, during the trip the president was accompanied by his wife and was rarely alone with his phone - unlike his frequent solitary nights at the White House.
London terror attacks: What we know and don't know
Borough Market, next to London Bridge, was busy at the weekend night with lots of people enjoying food and drinks in the bars. Speaking to the Press Association, Will Orton described being in a pub in the area and seeing people coming running inside.
"Just like during the Aso administration, Trump tweets mysterious "covfefe" tweet and sparks uproar", the tweet read. "Trump is right - he really does have the best words".