Bernie Sanders, the former US presidential election candidate, has congratulated Jeremy Corbyn, saying the election result is a sign of the world "rising up against austerity".

Prime Minister Theresa May was fighting to hold on to her job on Friday as British voters dealt her a punishing blow.

With no clear winner emerging from Thursday's parliamentary election, the wounded prime minister signalled she would fight on, despite losing her majority in the House of Commons. Her rival Jeremy Corbyn said she should step down.

"I am delighted to see Labour do so well," Mr Sanders told the Washington Post. "All over the world people are rising up against austerity and massive levels of income and wealth inequality.