Trump called Khan a “disaster” who should be thrown out of office, while re-posting a Twitter message written by right-wing British columnist Katie Hopkins on a series of shootings and stabbings that killed four people in London over three days, Presstv Reported.
“LONDON needs a new mayor ASAP,” Trump wrote. “Khan is a disaster - will only get worse!”
The mayor responded to Trump on Monday, saying it was “remarkable that you've got the president of the USA amplifying the tweets of a far-right activist, amplifying a racist tweet.”
"He's now a poster boy for the far-right movement and that should cause us huge concern,” he added.
"It's for Donald Trump to answer the question why he's obsessed with me; it's for Donald Trump to answer the question why he amplifies the tweets of far-right activists, why he amplifies racist tweets,” he said.
Responding to Trump, UK home secretary, Sajid Javid, said the US president should “stick to domestic politics.”
Khan, London’s first Muslim mayor, has been attacked by Trump since some three years ago, when Khan criticized then-candidate Trump for his proposed plan to ban foreign Muslims from entering the US.
Earlier this month, Trump reignited feud with Khan immediately after landing in London for an official visit. He called Khan in a Twitter message, “a stone cold loser" who has "done a terrible job.”