Dissident republicans could be raiding cash machines to fund attacks against police in the event of a no-deal Brexit, MPs have heard.
Independent MP Sylvia Hermon said police fear cash machines could be being stolen to fund weapons for attacks on officers and people along the Irish border.
The remarks came as Northern Ireland Secretary Karen Bradley faced pressure from the DUP to pursue changes to the Northern Ireland backstop.
Speaking in the House of Commons, the MP for North Down asked, "Has the minister been made aware by the Police Service of Northern Ireland that dissident republicans are responsible for the recent spate of thefts of ATMs across Northern Ireland and are intent upon using that stolen money to purchase weaponry to attack police officers and others along the border in the event of a no-deal Brexit?"
Northern Ireland Minister John Penrose said, "There has been a great deal of speculation about this matter.
"I think all I can say, and I hope she understands, in my response here is that policing obviously is an operational matter and there are ongoing and live police investigations into this as we speak, therefore I can't really go much further into it."
Earlier, DUP Westminster leader Nigel Dodds highlighted that MPs had supported an amendment to replace the backstop with "alternative arrangements" and asked if the Secretary of State still stood by it and whether she would encourage Prime Minister Theresa May to "adopt that approach".
Mr Dodds said, "I think in terms of a no-deal outcome, she'll have heard the Irish Taoiseach and indeed Michel Barnier say that in the event of a no-deal that there won't be any hard border on the island of Ireland and arrangements will be made to ensure checks and controls remain operationally away from the border.
"Does she understand the frustration of people, therefore, who say that in the event of a no-deal there'll be no hard border but they're insisting on a backstop, which could actually bring about the conditions they say want to avoid?"
Ms Bradley said she understood the "many frustrations" around the Brexit process, noting the Withdrawal Agreement is a "fair and balanced" way for whole of the UK to leave the EU.