Trump stated on Twitter Monday morning that London Mayor Sadiq Khan had offered a "pathetic excuse" and "had to think fast on his 'no reason to be alarmed' statement."
Trump's tweet renews his mischaracterization of Khan's statement to London residents following a vehicle and knife attack that left seven people dead and dozens injured. The mayor had told London residents not to be concerned by a stepped-up police presence in the city after the incident.
In a Sunday tweet, Trump mischaracterized Khan's remarks by suggesting the mayor had said there was "no reason to be alarmed" about the attack itself. Khan's spokesman said he was too busy to respond to Trump's "ill-informed" tweet.
On Monday, a spokesman for Khan responded to the latest statement from Trump, saying: "Nothing has changed since yesterday."
He said: "The mayor is focused on dealing with Saturday's horrific and cowardly attack and working with the police, the emergency services and the Government to keep London safe."
Asked if Trump was wrong to make the comments, British Prime Minister Theresa May said at a news conference Monday that "Sadiq Khan is doing a good job and it's wrong to say anything else - he's doing a good job."
Trump's latest missive at Khan was part of several Monday morning tweeted statements from the president. Trump also lashed out at his own Justice Department for seeking a "watered down" version of the travel ban he signed in March instead of a broader directive that was also blocked by the courts.
The war of words was the latest episode in a long simmering feud between Trump and Khan, a Muslim who was elected as London's mayor in May 2016. After his election last year, Khan tweeted criticism of then-candidate Trump's rhetoric, saying that his "ignorant view of Islam could make both our countries less safe. It risks alienating mainstream Muslims." Trump later challenged Khan to an IQ test during an interview on ITV.
Senior White House adviser Kellyanne Conway on Monday condemned what she called the media's "obsession with covering everything he says on Twitter and very little of what he does as president."
In an appearance on NBC's "Today Show," Conway said people should pay attention to what the president is doing, saying people in England had tried to inform authorities about the terrorists before the attacks happened.
"If you're going to see something and say something, it has to be followed by, do something," she said. "And this president is trying to do something to protect the people of this country."
Trump said he had spoken with May to express America's "unwavering support" and offer U.S. assistance as the British government works to protect its citizens and bring the guilty to justice.
British authorities say that have identified the three attackers but have not revealed that information publicly.