DUP leader Arlene Foster watches Britain's Prime Minister Theresa May deliver a speech at the Waterfront Hall in Belfast, Northern Ireland, July 20, 2018. Charles McQuillan/Pool via Reuters

BELFAST (Reuters) - The head of Northern Ireland’s Democratic Unionist Party on Friday vowed to veto any attempt to introduce a new regulatory barrier between the region and the rest of the United Kingdom, and said the European Union’s Brexit position was disgraceful.

“Any new regulatory barrier would be a matter for the Northern Ireland Assembly, where the DUP would veto any attempt to undermine the economic or constitutional integrity of the United Kingdom,” said Arlene Foster, whose party British Prime Minister Theresa May relies on for her majority in parliament.

“The Prime Minister is right to stand firm in the face of disrespectful, intransigent and disgraceful behaviour by the European Union,” Foster added in a statement. “The United Kingdom will not be treated in such a manner.”