Boris Johnson has held "frank" discussions with Northern Irish lawmakers over a controversial protocol in the Brexit Deal while visiting the devolved region.
The British Prime Minister's visit to Northern Ireland comes shortly before the centenary of Ireland's partition and the creation of the province in May but he did not meet with the leadership of Sinn Fein - the second largest party in Stormont.
Johnson visited a mass COVID-19 vaccination centre in the Co Fermanagh constituency of first minister Arlene Foster where she called on him to "stand up for Northern Ireland" and remove the "intolerable" Northern Ireland protocol, which has led to heightened tensions in the island recently.
The protocol establishes the trading regime that governs the Irish Sea since the UK withdrew from the European Union last year.
In order to ensure consistency with the terms of the Good Friday Agreement - which established an end to violence in Northern Ireland - and avoid a hard border on the island of Ireland, the protocol keeps the region under certain EU Customs Union regulations.
After the meeting, Mrs Foster described the PM as being in "listening mode" and "alive to the issues".
"Not a single unionist party in Northern Ireland supports this unworkable protocol," she said.
She said that the protocol, which is intended to retain the peaceful status quo, did not protect "the Belfast Agreement and its successor agreements" but has instead "created societal division and economic harm".
"Whilst grace periods have been extended unilaterally, we need a permanent solution so business can plan and the integrity of the United Kingdom internal market can be restored".
While speaking to the PM, Mrs Foster highlighted a school in Fermanagh which was unable to import trees from England. This is allegedly because of the bureaucracy over the transport of soil across the effective customs border down the Irish sea.
According to a spokesman for the PM, Northern Ireland Deputy First Minister, Sinn Fein's Michelle O'Neill, was invited to join discussions during Johnson's visit. However, the staunchly nationalist group did not take part.
O'Neill snubbed the PM's visit to Belfast after her own request for a political meeting with her and Sinn Fein leader Mary Lou McDonald was rejected.
"Mary Lou McDonald and myself have a long-standing request to meet with the British prime minister to discuss a number of commitments which he and his government have reneged on in the New Decade New Approach over this past year, and also his reckless and partisan approach to the Irish Protocol. He did not facilitate the meeting," Ms O'Neill said.
"I have no plans to meet with him today".
Sinn Fein MP John Finucane rejected the nationalist party's involvement with what he called a "day out for unionism" after Downing Street's rejection of a "professional, grown-up engagement" relating to issues such as the protocol.
"We're not in the business of engaging in a fairly superficial PR stunt, which is what the British prime minister invited us to do today", the North Belfast politician said.
"We have made the request to meet with him. I think it's insulting to the 770,000 people on this island who vote for us that he feels it appropriate to ignore and refuse that meeting".
However, this has seen customs declarations on goods going into Northern Ireland from Great Britain, such as checks on some products. Disruptions to trade have emerged as a result, seeing some firms finding it difficult to maneuver processes and administrations.
It has also caused frustration with Unionists who oppose the arrangement, claiming that it undermines Northern Ireland as a part of the UK's internal market.
Nationalist groups in the UK oppose scrapping the protocol and claim that the ongoing trade issues can be revised to accommodate a better situation for all parties involved.
UK government ministers have unilaterally extended the "grace period", which allows for the avoidance of customs checks for food and parcels going from GB to NI. The EU initially permitted this to continue until 1 April but it has now been extended by Westminster until 1 October.