BRUSSELS • U.K. Prime Minister Boris Johnson’s government and the European Union agreed to new terms for the country’s exit from the bloc Thursday, paving the way for a high-stakes vote in the British Parliament.

The accord was endorsed by the leaders of the other 27 EU countries at a summit here. Johnson now faces the formidable challenge of winning backing for the deal from Parliament.

After days of intense talks more than three years after Britain voted to leave the EU, the two sides struck a compromise intended to ensure a border doesn’t appear on the island of Ireland. It was the main sticking point in negotiations aimed at smoothing Britain’s split with its largest trading partner.

The breakthrough marks an unexpected turn of events in Britain’s tortured journey out of the EU and a victory for Johnson, who has pledged to deliver on the result of the 2016 referendum. It comes after weeks of at times acrimonious confrontations between U.K. and EU officials over the terms of Brexit, scheduled for Oct. 31.

The proposed deal would leave Britain freer to set its rules and strike trade deals independently from the EU.

The focus now shifts to Britain’s Parliament, where Johnson’s aides are busy selling the deal to both his Conservative Party and opposition Labour lawmakers before a vote scheduled for Saturday. Johnson urged lawmakers to vote through the deal “so that we can get Brexit done without any further delay.” A previous deal negotiated by Johnson’s predecessor, Theresa May, was rejected by Parliament three times.

But Johnson’s allies in Northern Ireland’s Democratic Unionist Party said they wouldn’t support the deal when it comes up for a vote, arguing that the agreement would weaken the bonds between Northern Ireland and the rest of the U.K.