The U.K. and the European Union have reached an agreement on new trade rules in Northern Ireland in an attempt to resolve a thorny issue that has fueled post-Brexit tensions in Europe and on the island of Ireland.

CNN reports the deal could potentially resolve the issue of imports and border checks in Northern Ireland, one of the most challenging and controversial aspects of the United Kingdom’s split from the EU. Northern Ireland is part of the U.K. but shares a land border with the Republic of Ireland, an EU member state.

Speaking at a press conference in Windsor, just outside London, Prime Minister Rishi Sunak said that the new deal, called the “Windsor Framework,” will deliver “smooth flowing trade” within the U.K., “protects Northern Ireland’s place” in the U.K. and “safeguards” the sovereignty of Northern Ireland.

European Commission President Ursula von der Leyen acknowledged the tense relations between the U.K. and EU since Brexit. She said that in order for the two parties to “make the most of our partnership” new solutions were needed. She pointed to the U.K. and EU’s cooperation on Ukraine and said that “we needed to listen to each other’s concerns very carefully.”

The purpose of the deal is to fix the issues created by the Northern Ireland Protocol, an addendum to the Brexit deal agreed by Boris Johnson and the EU in 2019. The protocol was created to prevent a hard border on the island of Ireland by keeping Northern Ireland aligned with the EU, meaning goods don’t need to be checked between the Republic and the province. The Windsor Framework will replace the Northern Ireland Protocol.

Sunak also announced a new “Stormont brake” that would allow Northern Ireland’s devolved government to pull an “emergency brake” on any new EU laws from being imposed on the province.