British Prime MinisterTheresa May gives a speech at 10 Downing Street after meeting with the Queen in London, Britain on June 9, 2017. British Prime MinisterTheresa May confirmed Friday afternoon she will form a Westminster government, helped by members of Northern Ireland's Democratic Unionist Party (DUP). (Xinhua/Richard Washbrooke)

LONDON, June 10 (Xinhua) -- British Prime Minister Theresa May's two co-chiefs of staff quit Saturday as the fallout from the Conservative's poor showing in this week's general election continued.

Nick Timothy and Fiona Hill who had been the main architects of May's disastrous election campaign announced within minutes of each other that they were stepping down from their roles.

Both had come under pressure from Conservative MPs to quit to avert May facing a leadership challenge that would threaten her future as prime minister.

Timothy, who was only appointed to the role last July, said in his resignation statement that he accepted the part he played in the results of the snap election.

Instead of the expected landslide victory May had expected, the Conservatives lost 13 seats and also the majority they held before the election, and its majority, leading to a "hung" parliament.

Timothy wrote: "I take responsibility for my part in this election campaign, which was the oversight of our policy program. In particular, I regret the decision not to include in the manifesto a ceiling as well as a floor in our proposal to help meet the increasing cost of social care."

He said he took responsibility for the content of the whole election manifesto.

Timothy's colleague as joint chief if staff, Fiona Hill, released a brief statement following her resignation from her role at 10 Downing Street.

She said: "It's been a pleasure to serve in government, and a pleasure to work with such an excellent prime minister. I have no doubt at all that Theresa May will continue to serve and work hard as prime minister, and do it brilliantly."

May announced Friday that she will form a new government, working with the 10-strong group of Democratic Unionist Party MPs from Northern Ireland.

Before the election, May had a working majority of 17. When the House of Commons assembles next week, May will instead lead a minority government, with a majority of just 2, made up of her own 318 MPs and the DUPs 10.