Sir Jeffrey Donaldson said, "There was never any justification for masked gunmen on the streets of Northern Ireland and there never will be.
When I outlined DUP action on the Protocol at the start of September I indicated that action was needed within weeks. At that time the European Union was saying that fresh negotiations were impossible.
Since then the EU have agreed to table fresh proposals and serious negotiations have re-opened with the UK Government. No reasonable person could deny that this represents significant and positive progress. That progress was secured through political action and not violence.
Our focus should be on restoring Northern Ireland's place fully within the UK internal market. If the EU refuses to agree to the restoration of Northern Ireland's constitutional and economic integrity then it will fall to the UK Government to meet its commitment in the NDNA agreement to do so through UK legislation.
That is the roadmap to securing removal of the Irish Sea border. Those engaging in thuggery only undermine these efforts and cement the Protocol more firmly in place."
Mr Shannon said, "Hi-jacking and burning a bus achieves nothing other than putting the life of a driver at risk and damaging an important local service to the people of Newtownards. There is absolutely no justification or excuse for masked and armed men on our streets and it must be condemned without qualification.
I have been speaking to police locally about this incident and it is vital that those responsible are brought to justice."