British Prime Minister Boris Johnson took an unexpectedly sharp tone on Saturday after discussing post-Brexit rules for Northern Ireland with European Union leaders, in a break from the message of unity that Group of Seven leaders have been trying to send during their summit this week.

“I’ve talked to some of our friends here today, who do seem to misunderstand that the U.K. is a single country, a single territory,” Johnson told Sky News. “I just need to get that into their heads.”

Johnson, who is hosting this year’s summit in England, said that E.U. nations needed to “understand that we will do whatever it takes” to protect Britain’s interests in the ongoing trade dispute that has been nicknamed the “sausage wars.” He threatened to invoke Article 16 of the Northern Ireland Protocol, a move that would mean unilaterally refusing to hold up Britain’s end of the deal.

While Johnson has made similar threats before, his tone and the timing of his statements came as a surprise to observers. The British leader has been trying to use the G-7 summit as an opportunity to smooth over global tensions, and the event is supposed to be an opportunity for powerful nations to display mutual respect and signal cooperation. And as the host of the summit, Johnson is expected to maintain a sense of gracious decorum and refrain from a war of words with other leaders.

“Johnson’s intervention shows Number 10 is keeping all of their options on the table,” said Mujtaba Rahman, an analyst with Eurasia Group. “As E.U. leaders hoped the G-7 bilaterals would help lower the temperature, Johnson’s rhetoric will be interpreted as escalation and intransigence.”

“Number 10” refers to the prime minister’s residence at 10 Downing Street.

Tensions between the E.U. and Britain increased in early May when the British government decided unilaterally to extend the grace periods for goods such as minced meat, poultry or eggs to travel to Northern Ireland from the rest of the United Kingdom without any sanitary checks. Previous arrangements between Brussels and London mentioned such goods would face such checks starting July 1 to maintain the “soft border” between Northern Ireland and Ireland, but the British government wanted to postpone them “at least until 2023.”

On Wednesday, the U.K.’s Brexit minister, David Frost, met in London with Maros Sefcovic, the European Commission’s vice president for interinstitutional relations. Both were unable to reach an agreement. The E.U. official said it could be possible to set up an arrangement in which Britain would temporarily remain aligned with E.U. sanitary rules, eliminating the need for 80 percent of the checks. But this possibility was repeatedly rejected by British officials, since it would requiring sticking with some E.U. regulations in the wake of Brexit.

European countries fear that Britain wants to use unilateral moves such as triggering Article 16 to renegotiate the Brexit deal. And they complain that Britain is dragging its feet when it comes to other commitments that it made during the Brexit negotiations. For instance, if customs and sanitary checks in the Irish Sea are being carried by British officials, Europeans have the right under the treaty to supervise those checks. But as of June, they still don’t have access to British customs.

“The problem is that we are six months in and the E.U. experts still don’t have access to most basic IT systems in order to do their jobs, in order for the E.U. to know what goods are moving where and so being able to evaluate the level of risks,” an E.U. official working on the implementation of the protocol said.

After largely managing to avoid the topic of Brexit for much of the G-7 summit, Johnson met on Saturday with European Commission President Ursula von der Leyen and European Council President Charles Michel. The meeting was entirely focused on the implementation of the Northern Ireland Protocol, an E.U. official said. Both officials spoke on the condition of anonymity because they were not authorized to speak publicly about the matter.

“We understand the need for solutions to ensure the flow of goods and the control checks between the U.K. and the single market,” the E.U. official said after the meeting, adding that the rhetoric needed to be “toned down.”

Johnson had a different take, telling Sky News that he felt that the E.U. was interpreting the treaty in a way that was not “sensible or pragmatic” and was having a “damaging impact” on Northern Ireland.

Still, he said, “I think we can sort it out.”

Karla Adam contributed to this report.

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