BELFAST (Reuters) - Irish nationalists Sinn Fein must compromise if Northern Ireland is to avoid a “speedy” return to direct rule from London, the head of the Democratic Unionist Party said on Thursday.

FILE PHOTO: Democratic Unionist Party DUP leader Arlene Foster speaks to media outside the Irish Consulate in Belfast, Northern Ireland August 4, 2017. REUTERS/Clodagh Kilcoyne

Irish nationalists Sinn Fein and the DUP have failed to reach agreement on reforming a power-sharing government since a March election and each has blamed the other for missing repeated deadlines.

Continued failure would force the British government to bypass the regional assembly and revert to direct rule from London for the first time in a decade, a move that could destabilize the political balance in the province.

The British and Irish governments, who are facilitating the talks, have warned that failing to reach an agreement would have “profound and serious” implications and limit Northern Ireland’s influence in Brexit negotiations, although no one is forecasting a return to serious violence.

“Unless agreement can be found very quickly then London will be required to take decisions,” Foster said in a speech to supporters in a Belfast hotel on Thursday evening.

“Northern Ireland simply cannot continue without democratic oversight and that means the speedy introduction of direct rule if agreement is not reached.”

The British government’s Secretary of State for Northern Ireland James Brokenshire has indicated he wants a resumption as early as next week to avoid a return to direct rule. But no date has been set for the talks.

Foster said that a series of “one-sided demands” by Sinn Fein had made progress impossible and that they must move to achieve a breakthrough.

“If we are to have an agreement then there will need to be a willingness on all sides to reach out in order to secure a durable outcome,” she said.

Sinn Fein’s leader in Northern Ireland, Michelle O’Neill, earlier on Thursday said her party was “entirely committed” to making the political institutions work.

But she set out a series of demands for Sinn Fein to agree to return to government, including the full implementation of earlier agreements between the parties, improved rights for Irish language speakers and the legalization of gay marriage.

“We need to see the implementation of outstanding agreements and an end to the denial of rights enjoyed by citizens everywhere else on these islands on language, marriage and access to coroner’s courts,” she said in a statement.

Foster said the DUP was willing to support “practical measures for the Irish language ... if we can reach a wider agreement on these matters.”

“However, what we cannot and will not do is simply agree to one-sided demands.”

Foster also suggested that as an alternative to a new round of talks, the devolved regional assembly could be put back in place immediately with legislation brought forward to address language and cultural issues to be agreed within a time limit.

O’Neill on Friday rejected the offer, which she said had been made several times before, and called instead for an immediate resumption of talks.

She welcomed Foster’s offer of practical measures to support the Irish language, but said the DUP should go further and guarantee Irish language rights in legislation.