Sir Jeffrey Donaldson has said he expects to receive a “definitive response” from the UK Government over issues of concern he has raised about the Windsor Framework in the near future.
The DUP leader said that response would determine whether his party could support a return of the powersharing institutions at Stormont.
But Sinn Fein vice president Michelle O’Neill has said she does not share optimism that Stormont could return in the autumn, and said a question remained over whether the DUP would share power with other parties in Northern Ireland.
The leaders were speaking following the latest round of party talks with the head of the Northern Ireland Civil Service Jayne Brady at Stormont Castle.
The talks over recent weeks have focused on laying the grounds for a possible return of Stormont in the context of a challenging budget situation.
The DUP collapsed the Stormont executive last year in protest at post-Brexit trading arrangements created by the Northern Ireland Protocol.
The Windsor Framework struck by London and Brussels earlier this year sought to reduce the red tape on goods entering Northern Ireland from the rest of the UK while maintaining the dual market access.
However, the DUP has insisted the new accord does not go far enough to address its concerns around sovereignty and the application of EU law in Northern Ireland and the party is maintaining its blockade of Stormont until it receives further assurances from the UK Government.
Northern Ireland Secretary Chris Heaton-Harris said recently he remains optimistic that the powersharing institutions could return this autumn.
Speaking at Stormont Castle, Sir Jeffrey said: “We continue to engage with the Government. After the Windsor Framework we set out our position. We indicated continuing concerns that we had.”
He said his party had put a number of proposals to the Government on how to deal with their concerns.
He added: “We are in ongoing discussions with the Government about those proposals, and we expect to receive a more definitive response from the Government very soon.
“Let’s see then if that provides the basis for us to move towards the restoration of the political institutions.
“But we must address the concerns that have been raised about how this Windsor Framework is going to work in practice, the impact it will have on our ability to trade with the rest of the United Kingdom and resolving those problems.
“We are waiting for the Government’s response and I expect that will happen within the summer, then we will see where we are.”
The DUP leader said the negotiations with the UK Government would continue over the summer.
He added: “This is a continuing engagement and I have made my summer available.
“I am free to meet with the Government whenever they need to meet.
“I want to get this done, it is my priority, and I will continue to work at this.”
Ms O’Neill said the DUP and the UK Government were engaging in a game of “chicken”.
She said: “There were four parties in that meeting today, three of which are ready to form an executive and have been for some time.
“The real question is are the DUP prepared to share power with the rest of us, deliver good public services, fight for workers and families right now who are dealing with the cost-of-living crisis.”
She added: “I would say that I don’t share the Secretary of State’s very optimistic overly optimistic assessment last week (about the return of Stormont this autumn), I don’t think there is any evidence to back that up.
“I hope that changes, I hope we do have a reformed executive, but I don’t think anybody was sitting in that meeting today under any illusions that anything had changed in terms of the DUP and the British Government’s game of chicken.”
She said the British and Irish governments needed to adopt a common strategy and work together to bring Stormont back.
Alliance Party deputy leader Stephen Farry said the current situation was the most serious which Northern Ireland had faced in 25 years.
He said: “We have a twin governance and financial crisis, we have a complete vacuum in terms of decision making and we have an unprecedented budget crisis facing Northern Ireland with huge levels of cuts.
“Northern Ireland is bleeding badly and this situation urgently needs to be resolved.
“An executive is not going to be a silver bullet, but all key stakeholders are stressing the importance of an executive.”
Ulster Unionist leader Doug Beattie warned that if the Assembly did not return this autumn, it may not return until after next year.
He said: “I will stick and I have stuck with my analysis that, from the conversations I’ve had, from the information I’ve gleaned, that we will have the executive back up and running by the autumn.
“That is the optimist in me. The pessimist in me is saying if we don’t have it up and running in the autumn, we’re not going to have it up this year, and if we don’t have it up this year, with a general election next year, we are not going to have it up next year either.”