The leader of the DUP has said that he had a "frank and open conversation, on a range of issues" with the Taoiseach.
Speaking at Government Buildings, after his first meeting with Micheál Martin as DUP leader, Jeffrey Donaldson said he made it clear that unionists' concerns around the Northern Ireland Protocol were "growing and certainly not diminishing".
Mr Donaldson said that the protocol continued to impact Northern Ireland's relationship with the rest of the United Kingdom.
Asked if he was willing to walk away from North/South Ministerial meetings if his concerns were not addressed, the DUP leader said that he would not like to see any political institutions collapse.
However he added that "we cannot sustain a situation where our relationship with the rest of the United Kingdom is being harmed on a daily basis".
Meanwhile, the Taoiseach said he believes concerns around the Northern Ireland protocol, expressed by the unionist community, are "sincere".
Micheál Martin said that he had a "a very good meeting" with Jeffrey Donaldson.
A range of issues were discussed, including legacy issues and the unfolding situation in Afghanistan.
Mr Martin said that their discussion on the Protocol was "very honest", "open" and "solutions driven".
Speaking outside Government Buildings, the Taoiseach said he indicated to the DUP leader that the mechanisms to resolve issues around the Protocol are contained within the EU/UK Trade Agreement.
"Our sense has been that the EU Commission has been consistent, flexible and ready to respond to the situation," he told reporters.
Welcomed new DUP leader @J_Donaldson_MP to Government Buildings this afternoon.— Micheál Martin (@MichealMartinTD) August 27, 2021
Wide-ranging discussions on the Protocol, legacy issues, North-South cooperation, COVID-19 and Afghanistan. pic.twitter.com/9aueWSWhDH
Mr Donaldson said that unionists cannot "reasonably be expected to work as normal on a north/south basis when our relationship with the rest of the United Kingdom is being harmed on a daily basis by this Protocol.
"That is simply the reality of the political situation that we face.
"I don't want to see a political crisis in Northern Ireland, I don't want to see the political institutions being harmed, I want to see a Northern Ireland where we move towards a more united community, but the Protocol is harming our capacity to build that united community."
Mr Donaldson said issues around the protocol need to be addressed, and quickly.
"We need to remove the border that has developed between Northern Ireland and Great Britain in trading terms, we need to recognise that for unionists that cuts across the very Act of Union itself, which is the very fundamental building block of our relationship with the rest of the United Kingdom.
"Unionists cannot in any circumstances support such a situation and therefore the Irish Sea border needs to be removed," added the DUP leader.
"We need to find practical solutions that will enable trade to return to normality between Great Britain and Northern Ireland, and at the same time put in place measures that protect the integrity of the EU single market.
"Those two situations are not mutually exclusive."
Additional reporting: PA