Khan was commenting as city mayors from across the Europe gathered in the British capital for a landmark conference on social integration, Xinhua news agency reported.
A spokesman at London’s City Hall said: “With Trump on his way to the White House, Khan has called for uniting communities to be put top of the political agenda at a time when more and more people are feeling left behind, disconnected and ignored.”
“The US election, following on from the EU referendum, has shown how fractious relations between communities across the western world have become with hundreds of millions feeling estranged from the political debate,” said the spokesman.
At the Social Integration Conference here, Khan said the politics of division must not spread to diverse cities like London.
He urged city leaders “to build bridges instead of walls” to help communities live better together.
Failure to do so risked losing the argument to the divisive political forces gaining pace in many countries across Europe and the world, he warned.
The conference is a major gathering of city mayors from across Europe, called to share ideas and solutions to create more cohesive communities.
Delegates include policy experts, city leaders and the mayors of Amsterdam, Athens, Brussels, Copenhagen, Ghent, Lisbon, Oslo, Rotterdam, Stockholm, Vienna, Liverpool and Bristol and the deputy mayors of Bordeaux, New York and Paris.
Opening the conference Khan said: “We have seen major political upheaval around the world in recent months, with the EU referendum in the UK and the presidential election in the US.”
“This has shown how politics is becoming more and more polarised with whole communities in cities across the world feeling increasingly disconnected and estranged from national politics.
“That’s why 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,” said Khan.