The Northern Irish party which props up British Prime Minister Theresa May's government says it will not support her Brexit divorce deal.
Democratic Unionist Party (DUP) leader Arlene Foster told Sky on Wednesday she could not sign up to something that would damage the Union.
In a separate statement, the DUP said: "We will not be supporting the government if they table a fresh meaningful vote."
The DUP said May's deal "poses an unacceptable threat to the integrity of the United Kingdom and will inevitably limit the United Kingdom's ability to negotiate on the type of a future relationship with the EU."
