This combo shows London Mayor Sadiq Khan (R) and US President Donald Trump.

London Mayor Sadiq Khan has rebuked US President Donald Trump, branding him a bully and slamming him for spreading "hatred and bile," as tensions resurface over Trump`s attacks on the United Kingdom, immigration, and London`s first Muslim mayor.

Sadiq Khan condemned Trump on Thursday for a long-running campaign of personal attack, after the US president recently called him "horrible, vicious, disgusting."

The London mayor added that Trump had repeatedly hurled "bile" not only at him but at Britain more broadly, particularly through inflammatory claims that Khan`s electoral success was due to immigration.

Khan further stressed that such rhetoric reflects deep hostility toward what he called the UK`s social fabric and democratic values.

Recalling lessons learned early in life, Khan said he would not be intimidated by attacks from Washington.

"The best way to deal with a bully, whether it`s in the playground or in the White House, is to stand up to them. You don`t get more respect from a bully by cowering," he stressed.

Khan added that silence is not an option when Trump targets London and its people, saying, "when somebody attacks my city, our citizens, our values, our way of life - when somebody makes certain generalizations about the followers of one faith - I think it`s incumbent to stand up to them."

The London mayor also mocked Trump`s shifting targets, suggesting the American president might redirect his hostility toward New York Mayor Zohran Mamdani, who is a Muslim.

"When you look at the animus, hatred and bile coming from President Trump towards me. I sort of assumed when Zohran was elected, President Trump would be two-timing me and spending time targeting Zohran."

Khan, whose parents came from Pakistan, also downplayed a reportedly cordial Oval Office meeting between Trump and Mamdani, characterizing it as mere "tactical diplomacy," not a genuine reconciliation, particularly after Trump had labeled Mamdani a "communist" during the campaign.

Responding to Trump`s obsession, Khan said, "I genuinely think he`s obsessed. And there have been many periods where he`s said horrible things and I`ve not responded because I`m just too busy to get involved in tittle-tattle, and this pathetic name-calling."

Last month, Trump reignited the long-running feud with Khan, saying that he "gets elected because so many people have come in [to the UK]. They vote for him now".

Back in September, Khan branded Trump "racist, sexist, misogynistic" and "Islamophobic" after the US president called him a "terrible mayor" who had "changed" London.