Jeremy Corbyn's Labour Party gave a stiff competition to the Tories by garnering 261 seats, a gain of 29, while the Conservatives lost 12 seats.
"What the country needs more than ever is certainty", the Conservative leader said after the shock outcome of Thursday's vote.
May's authority over her party was shattered by the election result.
Sterling plunged against the dollar and the euro as the election result created even more uncertainty over the whole Brexit process.
Results of the general elections in the United Kingdom are out with no party gaining a clear majority and though the Tories fell short, Prime Minister Theresa May says she will form government in the United Kingdom with the support of the Democratic Unionists (DUP).
And hundreds of protesters have descended on Downing Street and Westminster against the move.
The Conservatives finished the election with 318 seats, eight short of the 326 needed for a majority, and the party is now dependent on the 10 DUP MPs to ensure legislation can be passed through a hostile House of Commons. We have worked well with May.
Theresa May is trying to persuade the ten DUP MPs to enter into a formal coalition agreement with the Tories, as opposed to a less formal "confidence and supply" arrangement, ministers tell me. "Now lets get to work".
She later announced that her top ministers, including finance minister Philip Hammond, foreign minister Boris Johnson and Brexit minister David Davis, would remain in their positions.
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In 2016, the party's leader Arlene Foster said about the pro-marriage equality movement: 'They are not going to influence me by sending me abuse - in fact, they are going to send me in the opposite direction and people need to reflect on that'.
Tusk added on Twitter: "We don't know when Brexit talks start".
That deal may involve key concessions on Brexit - which would involve rewriting the government's plans just over a week before negotiations with the European Union begin.
May had threatened to walk away from the talks rather than accept a "bad deal", with Britain's exit bill and the fate of European Union citizens in Britain among the early obstacles.
In more recent times, former first minister Peter Robinson's wife Iris, then an MP, described homosexuality as an "abomination", she stated in Parliament that homosexuality is "viler" than child sex abuse.
Later, she said she "obviously wanted a different result" and felt "sorry" for colleagues who lost their seats.
Many in the party are sceptical of man-made climate change, especially of subsidies to renewable energy sources.
In an indication of the unease within the party about the link-up with the DUP, Scottish Tory leader Ruth Davidson said she had demanded a "categoric assurance" from the Prime Minister that gay rights would not be affected by a deal.
On the same website Ms Hill said: "I have no doubt at all that Theresa May will continue to serve and work hard as Prime Minister and do it brilliantly".
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