DUBLIN (Reuters) - Ireland’s prime minister appealed directly to Northern Ireland’s pro-British unionist community on Wednesday, saying Dublin would respect the territorial integrity of the United Kingdom amid concerns over how a Brexit deal would impact the province.

Measures to avoid a return to controls on the land border between the British province and EU-member Ireland are at the heart of conflict among UK politicians over whether to back a draft divorce deal struck on Tuesday.

An open border is one of the main principles of the 1998 Good Friday agreement that ended three decades of conflict between pro-British unionists and nationalists who favor a united Ireland.

Northern Ireland’s largest unionist party, which props up British Prime Minister Theresa May’s minority government, has questioned whether she can get parliamentary approval, saying Brexit cannot cut the province adrift from the rest of the UK.

“I know that for the unionist community in Northern Ireland, this is quite a difficult time. I know many of them may be feeling vulnerable, many of them might be feeling isolated and many of them might be quite worried about what may be agreed in the coming days,” Varadkar told parliament.

“I want to say to them that the Good Friday Agreement will be protected and that includes a recognition that we respect the territorial integrity of the United Kingdom and the principle of consent that there can be no change to the constitutional status unless a majority of people in Northern Ireland say so, and we’re very happy to have that written into any agreement.”

EU sources said the draft accord envisages a July 2020 decision on what would have to be done to safeguard an open Irish border, if a new trade deal is not in place after a post-Brexit transition runs its course.

Britain would have two choices: extend the transition period once beyond December 2020, possibly until the end of 2021, or enter a customs arrangement that would cover all of the United Kingdom but in which Northern Ireland would be aligned more closely with the EU’s customs rules and production standards.

If Britain’s cabinet supports the draft divorce agreement, a summit of EU leaders will more than likely be held on Nov. 25, Varadkar said, adding that “obviously a lot of things can go wrong today and over the next couple of days.”

While stressing that he did not want to say anything that might make things more difficult for May ahead of the cabinet meeting at 1400 GMT, Varadkar said EU negotiators had acted in Ireland’s vital national interests and taken its concerns on the border on board throughout the process.