BRUSSELS: European Union leaders formally agreed a Brexit deal at a Brussels summit on Sunday, urging Britons to back Prime Minister Theresa May’s package, which faces furious opposition in the British parliament.

“EU27 has endorsed the Withdrawal Agreement and Political Declaration on the future EU-UK relations,” Tusk said after less than an hour of the leaders’ summit.

The 27 leaders took barely half an hour to rubber-stamp a 600-page treaty setting terms for Britain’s withdrawal from the European Union on March 29 and a 26-page declaration outlining a future free trading relationship. May joined them shortly afterwards for what will be a brief meeting to seal the accord. “This is the deal,” European Union Chief Executive Jean-Claude Juncker told reporters on his way into the meeting, saying he believed May would get it through parliament and ruling out big new concessions. “Now it is time for everybody to take responsibility — everybody,” said Michel Barnier, the Frenchman who has ground out the withdrawal treaty over the past 18 months.

Juncker called it “a sad day”, saying Brexit was a “tragedy” and tough on both sides. “I believe that the British government will succeed in securing the backing of the British parliament,” Juncker said, declining to comment on what might happen if May fails. “I would vote in favour of this deal because this is the best deal possible for Britain,” he added.

In a sign of worries ahead, Lithuanian President Dalia Grybauskaite tweeted after the deal was endorsed in the summit chamber that the exit process was “far from over”. Barnier called the package a basis for close future ties, insisting: “We will remain allies, partners and friends.”

French President Emmanuel Macron said the Brexit vote showed Europe needed reform. He stressed that Paris would hold Britain to tight EU regulations, notably on the environment, in return for giving it easy trade access.

The departure of a nation long skeptical of deeper EU integration was, Macron said, neither a moment for celebration nor mourning, but Britons’ free choice. Dutch Prime Minister Mark Rutte, whose country is one of Britain’s closest trading partners, praised May’s handling of the difficult negotiations and said he was confident that she could see the deal through parliament in the coming weeks.

But he also had a warning for those in May’s Conservative party as well as the Labour opposition who argue that a better deal can still be done before Britain leaves in four months if lawmakers deny her minority government support on Brexit. “This is the maximum we can all do,” Rutte said, shaking his head when asked if the EU might make more concessions.

Saying the EU “hates” Brexit, Rutte said: “Nobody’s winning — we are all losing.” But, he said, the deal was an acceptable compromise for all that gave May a chance to clinch a solution. The biggest question now facing the EU is whether May’s divided minority government can steer the deal, which foresees London following many EU rules to keep easy trade access, through fierce resistance in parliament in the coming weeks from both supporters and opponents of Brexit.

Lithuanian President Grybauskaite said there were at least four possible outcomes if parliament blocks the package. She named three - that Britons would hold a second referendum, hold a new election to replace May or return to Brussels to try and renegotiate the package. A fourth is that Britain will simply crash out of the bloc on March 29 without legal clarity.