
Arlene Foster has accused the Irish Government of using Brexit to promote the idea of a united Ireland.
The DUP leader said that the Government was "using the negotiations to put forward its views on what it believes the island of Ireland should look like in the future".
Her comments come after Foreign Affairs Minister Simon Coveney told a parliamentary committee that he wants to see a united Ireland in his political lifetime.
Speaking to BBC Radio 4, Ms Foster said: "We've heard from the Foreign Minister of the Republic of Ireland talking about his aspiration for a united Ireland.
"He is entitled to have that aspiration but he should not be using European Union negotiations to talk about those issues.
"What he should be talking about are trading relationships moving forward."
When asked if she could imagine applying the rules of the EU customs union without being in it, Ms Foster said she "cannot accept any position after Brexit to say that Northern Ireland is any different to any other part of the union".
"I think it's wrong the Irish Government is saying it will not allow the process to move forward until it has certain things it demands," she added. "You can't have it both ways. Leo Varadkar is saying he won't allow the discussion to move to the next stage to talk about trade until he has a commitment in relation to the Border."
In a separate interview on Sky News, Ms Foster accused the Government of "cherry-picking" the Good Friday Agreement in its own interest.
"The fundamental of the agreement is that we had the principle of consent, which essentially means that it is for the people of Northern Ireland to decide whether they want to stay within the United Kingdom or otherwise," she said.