World leaders have congratulated Rishi Sunak on becoming the UK's first non-white Prime Minister, with Joe Biden describing the occasion as a "groundbreaking milestone".
The US President said "it matters" that for the first time a person of colour, who is also the child of Indian immigrants, has risen to the highest political office in Britain.
Mr Biden told an event in Washington on Monday night: "Whether it's the United Kingdom, where just today, we've got news that Rishi Sunak is now the Prime Minister. As my brother would say, 'go figure'."
He added: "Pretty astounding. A groundbreaking milestone. And it matters, it matters."
Mr Sunak's grandparents were from Punjab state before migrating to east Africa.
The family settled in the UK in the 1960s and Mr Sunak was born in Southampton in 1980.
He was announced as the new PM on Monday on Diwali - the Hindu and Sikh festival of light.
Indian Prime Minister Narendra Modi said: "As you become UK PM, I look forward to working closely together on global issues, and implementing Roadmap 2030.
"Special Diwali wishes to the 'living bridge' of UK Indians, as we transform our historic ties into a modern partnership."
Irish premier Micheál Martin said: "Congratulations Rishi Sunak on becoming leader of the Conservative Party.
"I look forward to working with you, as British PM, on the important issues we face on these islands, and globally."
Irish deputy prime minister Leo Varadkar also sent his congratulations to the new Tory leader.
The Tanaiste said: “You have worked hard to achieve this. These are challenging times of war, inflation, global uncertainty.
“I look forward to the UK working with Ireland and the EU as friends and allies in the years ahead.”
Mr Sunak won the Tory leadership contest without a vote being cast after rivals Penny Mordaunt and Boris Johnson dropped out, and replaced Liz Truss after an audience with the King in Buckingham Palace on Tuesday.
Indian media celebrated his victory, with New Delhi Television announcing "Indian son rises over the empire".
The India Today news channel took a swipe at the UK's economic and political turbulence, using the Hindi term for someone of Indian background: "Battered Britain gets 'desi' big boss."
