LONDON (AFP) - Irish nationalists Sinn Fein on Tuesday (July 4) accused British Prime Minister Theresa May of setting the Northern Ireland peace process back decades after a further delay in talks to form a new government for the province.

Michelle O'Neill, Sinn Fein's leader in Northern Ireland, said an agreement between May and the Democratic Unionist Party's 10 MPs in the London parliament to prop up her minority government was at fault.

"She is in hock to the DUP," O'Neill told reporters in Belfast in comments aired on national television.

Marathon talks to form a new power-sharing executive in Northern Ireland with Sinn Fein and the DUP were delayed yet again after the parties admitted they could not reach a deal before the summer recess.

"Sinn Fein are disappointed but not surprised that a deal has not yet been done. What this constitutes is a monumental failure on behalf of Theresa May.

"She has set back decades of work," O'Neill said.

Conservative leader May struck a deal with the ultra-conservative DUP last month after losing her parliamentary majority in a June 8 general election.

The British government has insisted that the deal has no bearing on the Northern Ireland peace process.

DUP leader Arlene Foster told a news conference in Belfast: "We are disappointed we don't have an agreement this afternoon... Hopefully we can come to an agreement later on in the year." .

IRELAND URGES DIALOGUE

The power-sharing executive in Northern Ireland is part of the 1998 Good Friday peace agreement that ended three decades of violent political conflict, broadly between Catholic Irish nationalists and Protestants backing the union with Britain.

Britain and Ireland are co-guarantors of the process.

Britain's Northern Ireland Secretary James Brokenshire said despite progress being made, differences remained.

"It is clear that these issues cannot be resolved quickly enough to enable an executive to be formed in the immediate term," he said in a statement.

Brokenshire had on Monday warned that if no agreement was reached he would be forced to draft a budget for the province and have it enacted by civil servants, but a day later said only that he would "reflect carefully" on how to manage public services.

Ireland's Foreign Minister Simon Coveney urged the DUP and Sinn Fein to keep talking over the next few weeks.

"The governments can support and encourage but, in the final analysis, it is only the parties themselves that can make an agreement with each other," he said in a statement.

"We are determined to play our part in supporting the resumption of the power-sharing government in Northern Ireland - and the sooner that happens the better."

Northern Ireland's executive collapsed in January when Sinn Fein demanded DUP leader Arlene Foster step aside pending a public inquiry over a botched green energy scheme and accusations of "arrogance" towards Irish nationalists.

Foster has refused to stand down.