The DUP “won’t be distracted” by a poster campaign urging against a “sellout”, party MLA Gordon Lyons has said.

Political posters stating “Stop DUP sellout”, condemned as “intimidatory”, have been put up across Northern Ireland, including outside the office of party leader Sir Jeffrey Donaldson in Lisburn and in Hillsborough village where multi-party talks resumed on Monday.

The DUP is taking part in long-running separate talks with the government over unionist concerns around post-Brexit trading arrangements.

In a social media post on Sunday, Sir Jeffrey said the poster had been put up “in the middle of the night” by TUV members.

He said: “I will not be intimidated or distracted by such shadowy behaviour any more than similar behaviour I have faced in the past by republicans.”

On Monday morning TUV leader Jim Allister told the BBC’s The Nolan Show that members of his party were involved in putting up the poster.

He said: “This is a bit of political activism to which there has been a huge overreaction.

“If there is no sellout afoot then no-one has anything to worry about.”

Speaking in Hillsborough on Monday evening after taking part in multi-party talks around Stormont finances, DUP MLA Gordon Lyons said he had concerns around how they were erected, but insisted his party would not be distracted.

“It doesn’t surprise me in many ways that people would try to do this. I of course have concerns and issues about the way in which those posters were put up by often hooded people in the middle of the night, but we’re not going to be distracted by that,” he said.

“We have had different deadlines thrown at us in the past, we have had threats thrown in the past, and now this.

“It doesn’t surprise me, I’m here to make sure that we get the best possible outcome for the people of Northern Ireland. That’s what we are all about, that’s what we want to achieve.”

Earlier, Ulster Unionist Party leader Doug Beattie condemned the erection of the posters, which he said have also been placed outside the homes of DUP politicians.

He referenced a previous incident where a noose was put around the neck on one of his election posters, and said his office windows were later smashed.

He cautioned against the potential outcomes of “raising the rhetoric”.

“These posters weren’t just outside DUP elected representatives’ offices, these were also outside some of their family homes and that has to be condemned,” he said.

“People may say this is not intimidatory, this is just a poster, but I have young staff who work for me and if there are posters outside my office it intimidates them, so whether they think it’s intimidatory or not, it is.

“I don’t think it’s the right tactic. Jim Allister has made his point abundantly clear, he gets plenty of airwaves to make that point and I have to respect his point of view.

“I don’t think these posters help in any shape or form.”