Corbyn says there's enough opposition in Parliament and in May's own party to topple the government.
"We have made good progress but the discussions continue", said DUP leader Arlene Foster.
Earlier this week during a speaking tour of the United Kingdom and Europe Sanders said he saw "a real similarity" between Corbyn's campaign and his own bid for the Democratic nomination in the 2016 US presidential election. May's gamble in calling an early election backfired spectacularly, as her Conservative Party lost its majority in Parliament.
May's Conservative Party won the most seats overall in the House of Commons, but fell well short of a majority.
The campaigners had had three scenarios in mind: The best-case scenario was forming a government, the second best was a hung parliament, and the worst case was the Conservatives on 380 seats, with Labour dropping to 190.
"As I reflect on the result, I will reflect on what we need to do in the future to take the party forward", May said before adding "I obviously wanted a different result".
Voter turnout in the election was at 68.7 per cent and young voters turned out in big numbers in this snap poll election.
"The mandate she has got is lost Conservative seats, lost votes, lost support and lost confidence", he said.
She had spent the campaign denouncing Mr Corbyn as the weak leader of a spendthrift party that would crash Britain's economy and flounder in Brexit talks, while she would provide "strong and stable leadership" to clinch a good deal for Britain.
Labour under him polled 40 per cent of the vote, the highest for the party since 1970, and only slightly behind Ms May's Tories.
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She also promised to deliver the changes she set out after the two recent terrorist attacks in Manchester and London, giving police more powers and tackling radicalisation. As the polls suggested a tightening race, pollsters spoke less often of a landslide and raised the possibility that May's majority would be eroded. Corbyn accused the Conservatives of undermining Britain's security by cutting the number of police on the streets.
He told the Sunday Mirror: 'I can still be Prime Minister. This is disappointing for Prime Minister Theresa May, who chose to call an early election to try to strengthen her hand in talks with the European Union on Brexit.