The New IRA has said they intend to target any infrastructure that appears along the Irish border, in an exclusive television interview.
Speaking to Channel 4's chief correspondent Alex Thompson, a masked figure representing the dissident republican group was interviewed on camera at a safe house.
The spokesman, who was wearing a balaclava, said he was speaking after meetings with the New IRA Army Council. His voice was dubbed by an actor.
He said any border infrastructure would be "a legitimate target for attack and armed actions against those infrastructures and against the people who are manning them".
Asked if this meant bombings and shootings, he said: "Yes. It's important to understand that this is a country under occupation by Britain.
"As in any colonial situation, people have the right to respond by all means necessary."
He rejected that a backstop that included a border down the Irish sea would be an improvement.
"I don't think you're understanding what I'm saying here. Regardless of the form of occupation, whatever kind of border there is. Be it soft or so-called hard border, that's irrelevant."
During the interview, he also said the New IRA apologised for the murder of journalist Lyra McKee who was shot dead in Londonderry earlier this year.