London mayor Sadiq Khan on Monday blamed a lack of integration between communities for fuelling the "divisive political forces" that led to the Brexit vote in Britain and the rise of Donald Trump.
Speaking on the sidelines of a forum in City Hall with mayors from around the world, he urged city leaders to take action or risk further backlash.
"There are populist parties around the world taking advantage of the concerns and anxieties people legitimately have... we (Britain) chose to leave the European Union and we've had a very divisive U.S. presidential election," he told AFP in an interview.
"We've seen with social and scientific advances the globalised northern countries doing very well, but within those countries people feeling they're not sharing the fruits of that prosperity," he added.
"We should be making sure that we integrate far better than we currently do," said Khan, the first Muslim mayor of a Western capital, who was elected in May.
U.S. President-elect Trump and leaders of the Brexit campaign both focussed on immigration concerns in the run up to their shock victories.
Trump vowed to build a wall on the Mexican border and impose a moratorium on Muslim immigration into the U.S. while Nigel Farage -- called "Mr Brexit" by his ally Trump -- caused outrage during the EU referendum campaign by unveiling a poster showing a line of refugees under the words "breaking point".
A recent study by Ted Cantle, an expert on inter-cultural relations, found that some British cities were "tending more towards ghettoisation... as the minority population continues to grow and the majority continues to relocate".
Khan had previously rejected Trump's claims that parts of London had become "no-go areas" because of ghettoisation and said on Monday that political leaders should be "building bridges rather than walls".
"As city leaders, as leaders generally, we should be bringing people together," Khan said, while adding that he would be willing to meet the incoming U.S. leader.
Khan was hosting mayors from around the world at a conference to promote more integrated communities, telling them to tackle concerns over immigration head on.
"It's not good enough to simply dismiss these feelings as prejudice or backward, we need to really understand why people feel the way they do," he told the conference at his City Hall office.
"We need to see real leadership in cities around the world if we are to avoid communities becoming increasingly divided," he added.
"Now, more than ever, we need to build a strong sense of social solidarity within our cities -- a renewed sense that we are united as neighbours and citizens."