Sinn Fein Leader Mary Lou McDonald and Deputy Leader Michelle O'Neill held a news conference after meetings in Brussels with European Union Chief Brexit Negotiator Michel Barnier.
"We require, and I believe that we have been given, a very strong commitment that the protections contained within the backstop will be held constand," said McDonald.
She reiterated that it is important Dublin "holds firm on this issue".
Barnier did not appear at the meeting.
Watch the full conference in the video player above.