London (CNN) UK Prime Minister Theresa May finally gave in to the intense political pressure over her failure to secure Britain's withdrawal from the European Union, announcing her resignation in an emotional address to the nation on Friday.

Standing at a lectern in Downing Street, May said she deeply regretted not being able to deliver Brexit, the issue that brought her to power in 2016 and which consumed her premiership in the three years since.

May said she would quit as leader of the Conservative Party on June 7, but would stay on as Prime Minister until a successor is chosen . That process will be completed by the end of July, her party said.

In her speech, May said she had done everything she could to convince Members of Parliament (MPs) to back her thrice-rejected Brexit deal, but acknowledged that she had failed.

"I tried three times. I believe it was right to persevere, even when the odds against success seemed high. But it is now clear to me that it is in the best interests of the country for a new Prime Minister to lead that effort," she said.

"It is, and will always remain, a matter of deep regret to me that I have not been able to deliver Brexit."

May said it would be down to her successor to find consensus where she could not, and urged all sides to compromise. "I will shortly leave the job that it has been the honor of my life to hold -- the second female Prime Minister but certainly not the last," May said, her voice cracking with emotion.

"I do so with no ill-will, but with enormous and enduring gratitude to have had the opportunity to serve the country I love," she said, bursting into tears as she left the lectern and walked back into Number 10.

Cabinet withdrew support

May breaks down during her statement outside 10 Downing Street on Friday.

May was forced into making Friday's announcement after losing the support of her Cabinet, many of whom were fed up with the ongoing turmoil over Brexit.

The last straw for Cabinet ministers appears to have been the latest version of May's Brexit plan, which she unveiled on Tuesday. In an attempt to win over opposition lawmakers, May offered the House of Commons the chance to vote on a second referendum -- a concession that was bitterly opposed by some senior members of her government.

Her fate was sealed by the leadership of the 1922 Committee -- which represents the interests of rank-and-file lawmakers in May's Conservative Party -- who threatened to change party rules to allow a vote of no-confidence. May survived an earlier confidence vote in December last year, and under current rules was immune to challenge for another year.

Leadership race begins

Boris Johnson is a leading candidate to replace May.

May's announcement sets off a frantic race to succeed her. Conservative MPs will vote on their preferred candidates by the end of June, the party said. The top two choices will then be put before the wider party membership who will choose the leader by the time Parliament breaks for summer recess on July 20. The winner will then replace May as Prime Minister.

One leading candidate is Boris Johnson, the wily former Foreign Secretary who commands significant support among grassroots members of the party.

Johnson has bitterly opposed the withdrawal deal that May negotiated with the EU, and resigned from her Cabinet over it. On Friday, he described May's statement as "dignified" and said "it is now time to follow her urgings: to come together and deliver Brexit."

Graham Brady, the chairman of the 1922 committee of backbenchers, said he was standing down from his position in order to consider a leadership bid.

Tributes from colleagues

A number of May's Cabinet members, including potential candidates in the race to replace her, paid their tributes on Twitter.

Amber Rudd, who serves as Work and Pensions Secretary, praised May's "great courage," while Home Secretary Sajid Javid said no one had "a greater sense of public duty than the Prime Minister."

Prominent Brexiteer Andrea Leadsom, who resigned as Leader of the House of Commons on Wednesday, said May's speech illustrated "her total commitment to country and duty."

But it's unclear whether the next Prime Minister will have any luck reopening May's withdrawal deal, which Brussels has insisted is locked down. May's successor will face the same deadlocked House of Commons, which has repeatedly rejected her plan but failed to vote in favor of any kind of alternative.

That may raise the prospect of a new Conservative leader calling a general election in an attempt to break the impasse.

UK opposition Labour Party leader Jeremy Corbyn jumped at the prospect after May's speech, tweeting: "Whoever becomes the new Tory leader must let the people decide our country's future, through an immediate General Election."

Some pro-Remain politicians expressed concern that a Brexiteer could soon take May's place and push Britain towards a hard Brexit.

"The prospect of an even more hardline Brexiteer now becoming PM and threatening a no deal exit is deeply concerning," Scotland's First Minister Nicola Sturgeon said on Twitter.

European reaction

European leaders responded warily to the news. Outgoing European Commission President Jean-Claude Juncker encouraged Britain to accept May's Brexit deal during an interview with CNN on Wednesday , adding that it was more important to "to find an agreement" rather than replace the Prime Minister.

By Friday, a European Commission spokesperson said May's speech left Juncker "without personal joy."

"Theresa May is a woman of courage for whom he has great respect," the spokesperson said.

French President Emmanuel Macron sent May a personal message expressing his support and gratitude, an Elysee Palace spokesperson told CNN.

The Elysee praised Theresa May's "courageous" efforts to implement Brexit "in interest of her country and being respectful of her European partners".

"France stands ready to work with the future British Prime Minister on the entirety of European and bilateral issues", the Elysee message said.

The message ended with a reminder that the proper functioning of the EU was the priority and "that rejection votes without alternative project lead to stalemates."