DUP leader Sir Jeffrey Donaldson has said his party will "study the detail" of the new deal between the UK and European Union on Brexit's Northern Ireland Protocol.
He said "significant progress" had been made in addressing unionist concerns over the Irish Sea trading arrangements but "key issues of concern" also remain.
Prime Minister Rishi Sunak and EU chief Ursula von der Leyen finalised the new agreement during a summit at Windsor.
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The deal, named the "Windsor Framework", includes a new red and green-lane system and an "emergency brake" for Stormont on future changes to EU goods rules applying to the region.
But European Commission president Ursula von der Leyen said the changes to the Protocol still include a role for the European Court of Justice – a key issue for the DUP.
For the past year the party has blocked Stormont power-sharing in protest against the Protocol, which angered unionists for introducing new trade barriers between Great Britain and Northern Ireland.
In a statement Sir Jeffrey said: "Over 18 months ago the Democratic Unionist Party outlined seven tests which at the time I indicated would be the basis upon which we would judge any agreement between the United Kingdom and the European Union.
"It is now one year since we withdrew our First Minister from the then Northern Ireland Executive to send the clearest possible signal that we did not support the Northern Ireland Protocol and that we were not prepared to implement that which was disastrous for Northern Ireland.
"Since the imposition of that Protocol many, including the Government, the European Union and indeed those early cheerleaders for it in Northern Ireland have come to recognise that it could not have been made to work, had upset the delicate political balance in Northern Ireland and was not supported by the unionist community in Northern Ireland.
"Our judgement and our principled position in opposing the Protocol in Parliament and at Stormont has been vindicated. Undoubtedly it is now recognised that the Protocol does not work. When others said there would be no renegotiation and no change our determination has proved what can be achieved.
"We would like to thank the Prime Minister, and his predecessors for their work and significant engagement to date.
"We welcome the publication of the outcome of the Government's negotiations with the EU which ends a period of speculation and spin, often from those who know little about Northern Ireland.
"In broad terms it is clear that significant progress has been secured across a number of areas whilst also recognising there remain key issues of concern. There can be no disguising the fact that in some sectors of our economy EU law remains applicable in Northern Ireland.
"The DUP will want to study the detail of what has been published today as well as examining the detail of any and all underpinning legal texts. Where necessary we stand ready to engage with the Government in order to seek further clarification, re-working or change as required.
"Ultimately the party will now assess all these proposed outcomes and arrangements against our seven tests, outlined in our 2022 Assembly election manifesto, to determine whether what has been published meet our tests and whether it respects and restores Northern Ireland's place within the United Kingdom."
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