Sinn Fein have blamed ties between the Democratic Unionist Party (DUP) and the Tories for the fact that talks to secure a deal to restore power-sharing at Stormont have ended in failure.
Suggesting the DUP's recent decision to support the minority Tory government had "contributed" to the breakdown of talks Sinn Fein's Northern Ireland leader Michelle O'Neill said the inability to reach a deal was a "monumental failure" by British Prime Minister Theresa May.
Ms O'Neill said: "She has set back decades of work that has been done here throughout the years and it's a consequence, as we all know, of the DUP supporting the Prime Minister and the Prime Minister in turn supporting the DUP."
The DUP has cited Sinn Fein's "excessive demands" as the reason for the delay in reaching a deal.
A series of deadlines have already been missed to restore multi-party devolved government in Northern Ireland and the latest breakdown in talks means a deal is now expected to have to wait until at least the autumn.
DUP leader Arlene Foster expressed disappointment that an agreement to restore power-sharing has not been reached.
She said her party would continue to work on issues over the summer and "hopefully we can come to an agreement later on in the year".
Northern Ireland Secretary James Brokenshire said he remained hopeful a deal would eventually be reached, saying that while restoration of power-sharing would not happen in the "immediate term" both parties had indicated a "desire to remain engaged and to find a way to return to and resolve these issues".
The sign-off of both the DUP and Sinn Fein is required to form a devolved government but the parties are said to remain at loggerheads over a range of issues including proposals to introduce an Irish Language Act and the DUP's opposition to lifting the region's ban on same-sex marriage.