The U.K. government said working out what happens to the Irish border after Brexit will only be possible once the bloc agrees to discuss a new trade deal, rejecting a demand from the European Union. Brexit Secretary David Davis said it won’t be possible to address the question of the border between Northern Ireland and the Republic of Ireland—or to finalize the so-called exit bill—until the terms of future trade between Britain and the EU are clearer. “We now must start talking about our future relationship,” Davis told a conference in London on Tuesday. “The Northern Ireland border cannot be fully addressed if we’re not taking into account the shape of our future partnership with the European Union. The final resolution of the financial settlement depends on it because nothing is agreed until everything is agreed.” His comments came as the U.K. seeks to push talks on from the divorce terms to a future trade deal and transitional phase. Negotiations are stuck over the question of how much Britain will pay when it leaves the EU, the rights of European citizens and the question of avoiding a hard border in Ireland. On Monday, EU chief Brexit negotiator Michel Barnier said Britain must provide the answer to how different customs regimes can operate on the island once Northern Ireland leaves the bloc along with mainland Britain in 2019. Both the U.K. and the EU have said they do not want to see a return to the border between the north and the south. “We are working hard to find that unique solution we need on the issue,” Prime Minister Theresa May’s spokesman James Slack said. “It’s in the interests of the U.K. and the EU 27 to move these talks on.” May wants the EU to agree to allow talks to move to the second phase—discussing trade and transitional arrangements—at a key summit of leaders in Brussels next month.