US presidential hopeful Hillary Clinton on Saturday joined a number of politicians from around the world in congratulating Sadiq Khan on becoming the first Muslim mayor of London.
"Son of a Pakistani bus driver, champion of workers' rights and human rights, and now Mayor of London. Congrats, @SadiqKhan. -H," Clinton, the Democratic front-runner, said on Twitter.
Khan of Britain's centre-left Labour Party was sworn in earlier Saturday, promising to be a "mayor for all Londoners" during a multi-faith service.
"I can't believe the last 24 hours. I want to start my mayoralty as Iintend to go on. I want this to be the most transparent, honest and accessible administration London has ever seen," said Khan, 45, during a ceremony at the city's Southwark Cathedral.
Khan also hoped to inspire other Muslims.
"I'm hoping the result on Thursday encourages young people to get involved in mainstream politics, encourages Londoners of Islamic faith and other minority communities, encourages British Muslims and others to get involved in civic society and get involved in mainstream politics," he said in an interview with Sky News.
The news of his election was also welcomed in the home country of Khan's parents.
Bilawal Bhutto, the son of former Pakistani prime minister Benazir Bhutto and leader of the Pakistan People's Party, tweeted: "Congratulations @SadiqKhan 4 being elected mayor of London ... British Pakistanis need +ve rolemodel."
Pakistani cricketer-turned-politician Imran Khan tweeted: "Congratulations to Sadiq Khan on becoming Mayor of London."
Imran Khan was married to Jemima Goldsmith, the sister of Sadiq Khan's opponent, Zac Goldsmith.
Jemima had showed herself disappointed with her brother's performance and conduct, tweeting: "Sad that Zac's campaign did not reflect who I know him to be- an eco friendly, independent- minded politician with integrity."
Other wellwishers to welcome Khan's election included fellow mayors.
"Sending congratulations to London's new Mayor and fellow affordable housing advocate, @SadiqKhan. Look forward to working together!," tweeted New York Mayor Bill de Blasio.
From Paris, Anne Hidalgo offered her "felicitations," saying, "I'm convinced that his humanism and his progressivism will benefit Londoners!"
After his election victory, Khan said that "London is the greatest city in the world."
The son of Pakistani immigrants who grew up on a London council estate said he was both "proud" of the city and "deeply humbled" by his election.
"I never dreamt that someone like me could be elected as mayor of London," he said.
Khan, whose father was a bus driver, studied law and became a human rights lawyer before being elected as a member of parliament for the Labour Party in 2005.
"I want every single Londoner to get the opportunities that the city gave to me and my family - the opportunities not just to survive, but to thrive," Khan pledged.
He promised Londoners "the opportunities to build a better future for you and your family, with a decent and affordable home and a comfortable commute you can afford, more jobs with better pay, not just being safe, but feeling safe, cleaner air and a healthier city."
Khan received 57 per cent of the vote, beating his Conservative rival Zac Goldsmith, who finished with 43 per cent.
Goldsmith said he was naturally "disappointed ... by the result," but went on to congratulate Khan. "I wish him well as he sets out to build on the successes that we have seen under Boris Johnson and to take them even further," he said.