British Prime Minister Boris Johnson said Thursday that leaders have reached a deal on the United Kingdom's exit from the European Union.

"We've got a great new deal that takes back control - now Parliament should get Brexit done on Saturday so we can move on to other priorities like the cost of living, the [National Health Service], violent crime and our environment," Johnson tweeted, saying the deal would allow the U.K. to leave by an Oct. 31 deadline.

Any deal must still be approved by the U.K. and EU parliaments. Northern Ireland's Democratic Unionist Party, which will likely need to approve the deal for it to pass the British Parliament, said it could not support the proposed deal "as things stand," according to the BBC.

Labour Party Leader Jeremy Corbyn, meanwhile, said the proposed agreement sounded "even worse" than the one proposed by former Prime Minister Theresa May and called on Parliament to reject it, the BBC noted.

Under a law passed by Parliament in September, the prime minister must request an extension of the deadline by Saturday if Parliament has not yet agreed to a deal. However, Johnson plans to ask EU leaders to reject extension requests, according to the BBC, which cited sources within his office.

Johnson said the proposed deal would eliminate the so-called backstop regarding the Northern Irish border, a major bone of contention during negotiations.

"The people of Northern Ireland will be in charge of the laws that they live by, and - unlike the backstop - will have the right to end the special arrangement if they so choose," he tweeted.