UK Prime Minister Theresa May is in Northern Ireland where she is trying to reassure people that she can secure a Brexit deal that will avoid a hard border on the island of Ireland.
May told business leaders in Belfast the "need for changes to the backstop is the key issue" adding that she is not arguing to scrap it.
In January, MPs rejected the deal May had agreed with the EU over concerns about the backstop, an insurance policy that is designed to avoid a hard border.
May will return to Brussels on Thursday to seek fresh concessions on the Irish backstop.
But EU leaders have indicated they will not renegotiate the Brexit deal.
May also said she "would not compromise Northern Ireland's position in the UK" and that she does not want to create an effective border between Northern Ireland and Great Britain, which is why she opposed the EU plan for a Northern Ireland-only backstop.
May said she will hold talks with all of Northern Ireland's political parties on Wednesday.
The prime minister also said that she is committed to the Good Friday agreement, a peace deal signed in 1998 to end the period of conflict in Northern Ireland known as the Troubles.
May addedcthat she wants the strongest possible bilateral relationship with Ireland, which she says, has a deeper relationship with it than any other member of the EU27.
She also floated the idea of a joint UK-Ireland World Cup bid for 2030.