EU says it 'will need to respond' if UK changes post-Brexit deal on Northern Ireland

The EU said Tuesday it "will need to respond with all measures at its disposal" if Britain goes ahead with unilateral changes to the part of the Brexit deal on Northern Ireland.

The announcement, made by British Foreign Secretary Liz Truss, "raises significant concerns," European Commission Vice President Maros Sefcovic said in a statement.

"The (Northern Ireland) Protocol is an international agreement signed by the EU and the UK. Unilateral actions contradicting an international agreement are not acceptable," he said.

The statement did not outline what action Brussels was contemplating, but analysts say possible options include legal action, punitive tariffs or even tearing up the entire EU-UK post-Brexit trade agreement.

Sefcovic pointed out that the protocol is "an integral part" of the Brexit deal, which was "the necessary foundation" to the later trade agreement.

He said that Brussels recognises "the practical difficulties" in implementing the protocol and remains ready to negotiate "joint solutions within the framework" of the agreed text.