Keep calm, Madam prime minister, and Brussels will carry on.

European Council President Donald Tusk on Friday evening sought to contain the damage of a disastrous EU leaders' summit in Salzburg, Austria, that plunged the Brexit negotiations into new acrimony.

Faced with headlines at home declaring a "humiliation" by her EU colleagues, U.K. Prime Minister Theresa May came out fighting to declare an "impasse" in the talks, demanding "respect" for the U.K. and issuing a warning that she would not "break up my country."

Tusk said he was issuing his statement "as a close friend of the U.K. and a true admirer of P.M. May," but he also pushed back hard on the prime minister's complaints. The Council president said she had been well aware "for many weeks" of the EU's objections to the core economic proposals in the Brexit plan agreed with her Cabinet back in July at her Chequers country residence, and the EU's insistence of a legally watertight plan to avoid a hard border in Northern Ireland.

Tusk said he still believes a deal is possible, but he remained unbending on the issues of the Ireland border and future trade relationship.

The value of the pound dropped sharply following May's statement.

"We studied the Chequers proposals in all seriousness," Tusk said. "The results of our analysis have been known to the British side in every detail for many weeks. After intensive consultations with member states, we decided that for the good of the negotiations, and out of respect for the efforts of P.M. May, we will treat the Chequers plan as a step in the right direction."

Tusk, however, then referenced his public statement to reporters in Salzburg before the start of the summit, in which he praised May's proposals on security and foreign policy, but added: "On other issues, such as the Irish question, or the rules of economic cooperation, the U.K.'s proposals will need to be reworked and further negotiated.”

May’s forceful defense of her country seemed to win her at least some initial praise at home, where her speech was viewed as rightly scolding Brussels for not showing sufficient respect to the United Kingdom. “The prime minister has shown steely resolve at the 11th hour and is standing up to the EU bullies," said Brexiteer backbench MP Jacob Rees-Mogg.

But in a sign that markets are uneasy about the increased tension on display between London and Brussels, the value of the pound dropped sharply following May's statement.

In his new statement on Friday, Tusk also rebuked May for taking too-hardline a stance in a recent op-ed published in the German newspaper Die Welt, and in a statement that she made to her fellow EU leaders at a dinner in Salzburg Wednesday night. In that presentation — to which leaders gave no immediate response — May said there would be no second referendum on Brexit, and that her Chequers proposal is the only option on the table.

Tusk and other EU leaders, notably German Chancellor Angela Merkel and French President Emmanuel Macron, repeated their opposition to May's plan at news conferences before leaving Salzburg Thursday. Those remarks apparently left May feeling ambushed by an unexpected diplomatic pile-on.

In his new statement, Tusk said the EU has always respected Britain's decision to leave, and that he still believes a deal was possible, but he also said: "The U.K. stance presented just before and during the Salzburg meeting was surprisingly tough and in fact uncompromising. The response of the EU27 leaders was to reiterate our trust in chief negotiator Michel Barnier and to reiterate our position on the integrity of the Single Market and the Irish backstop [the proposal to avoid a hard border between Ireland and Northern Ireland in perpetuity]."

Other EU officials on Friday continued to express their own surprise at the level of surprise May expressed in Salzburg over the EU position, given it merely reflected principles Brussels has articulated since the very start of formal negotiations in July 2017. On Friday, they also frowned on the breathless coverage in the British press.

"We do not at all share the assessment of the British media of the Salzburg outcome and spirit," one EU official said. "The Commission is and will continue to be in a constructive mood, as outlined in the president's State of the Union speech." In that speech, Jean-Claude Juncker praised May's proposal, saying it could form the basis for a new relationship. “The United Kingdom will never be an ordinary third country for us,” he said.

The EU's hope had been that the summit would showcase a renewed, shared commitment to completing a deal, and leaders for most of the gathering had tried to minimize any tensions. The mood shifted, however, after a lunchtime meeting on Thursday where the consensus was that May was too uncompromising. Even then, however, Tusk and other leaders, including Juncker, continued to express optimism.

On Friday, Tusk concluded his statement on a positive note, stressing his admiration for May and conviction that a deal was still attainable.

"While understanding the logic of the negotiations, I remain convinced that a compromise, good for all, is still possible," he said.