(Corrects year of Good Friday agreement in lead)
LONDON, June 15 (Reuters) - Irish political party Sinn Fein said on Thursday it would oppose any deal between British Prime Minister Theresa May and the Democratic Unionist Party in Northern Ireland that undermines the 1998 peace deal known as the Good Friday Agreement.
"We will oppose any deal which undermines the Good Friday agreement," Sinn Fein's president, Gerry Adams, told reporters outside May's Downing Street residence.
"We have just finished a meeting with the British prime minister and her secretary of state and we told her very directly that she was in breach of the Good Friday agreement," Adams said.
May is looking for support from the DUP after failing to win a majority for her Conservative Party in last week's elections.
The DUP represents people in Northern Ireland who wish the province to remain part of the United Kingdom, while Sinn Fein wants Northern Ireland to be administered by the Irish Republic. (Reporting by David Milliken and Kate Holton, editing by Elizabeth Piper)