Lewis Lukens, the acting United States ambassador to the UK (a permanent one has yet to be confirmed) tweeted: "I commend the strong leadership of the Mayor of London as he leads the city forward after this heinous attack".
Trump's comments drew widespread scorn in Britain but the U.S. leader went on the attack again on Monday, saying in a tweet: "Pathetic excuse by London Mayor Sadiq Khan who had to think fast on his "no reason to be alarmed" statement".
In one instance, he leveled an inaccurate criticism of London Mayor Sadiq Khan, saying the mayor was telling people there was "no reason to be alarmed" about the attack.
Mr Khan's spokesperson had described the first round of presidential tweets as "ill-informed" - and said they had deliberately taken the mayor's remarks out of context.
On Sunday, a spokesman for the London mayor said he was working with the police, emergency services and government to coordinate the response to the attack, and had "more important things to do" than to respond to Trump. "MSM is working hard to sell it!", Trump said in a Tweet.
"I think Sadiq Khan is doing a good job and it's wrong to say anything else - he's doing a good job", she told reporters at an election campaign event in London.
After his election past year, Khan tweeted criticism of then-candidate Trump's rhetoric, saying his "ignorant view of Islam could make both our countries less safe".
Penn State trustees implement new reforms on Greek life
The biggest change is that the university is taking over disciplining of the Greek community, including sanctions for misconduct. As noted, the Administration and its Trustees knew about the problems and the issues but chose to turn a blind eye".
In the hours after the attack, US President Mr Trump tweeted to his 31.6 million followers using it as a reason to push his travel ban on visitors and refugees from six mainly Muslim countries; offer support to London; call for the end of "political correctness"; bring guns into the debate and finally to twist Mr Khan's words and to criticise him.
Trump has used the policy, stalled now in USA courts, as an example of the sort of toughness that he says Khan refuses to show amid terrorism attacks that are riling the United Kingdom.
The ex-LBC radio host has appeared on the Fox News channel in the wake of the attack on Saturday night, on a programme that Trump is known to watch religiously.
That evening, Trump took to social media to blast Khan for his response to the attack.
Though Clinton did not name Trump particularly, her comments seemed to reference the president's tweets.
While attending a fundraiser for Rep. Elijah Cummings' (D-Md.) youth program, she added, "It is time for steady, determined leadership like we are seeing from London's mayor and local authorities".
At least 7 dead and 48 wounded in terror attack and Mayor of London says there is "no reason to be alarmed!"
The Trump administration last week formally asked the Supreme Court, the highest court in the US, to allow the ban to take effect, arguing that restricting immigration by refugees and visitors from Iran, Libya, Somalia, Sudan, Syria and Yemen is necessary to protect USA national security.