The European Commission is to seek further reassurances from authorities in Northern Ireland over the safety of EU customs and veterinary staff working at ports there, following reports of intimidation and graffiti near the ports.
European Union staff, who have been supporting local officials in implementing the Northern Ireland Protocol, have still not been informed when they can return to their duties.
Meanwhile, EU sources have described a letter from UK Cabinet Minister Michael Gove as an apparent ultimatum to the EU to agree to sweeping changes to the protocol.
These developments have fed into a wider escalation in tensions over the impact of the Northern Ireland Protocol.
After a virtual meeting between Mr Gove, his EU counterpart Maros Sefcovic, and the North's First and Deputy First Ministers last night, all sides agreed that staff implementing the protocol should not be subject to threats.
However, EU sources believe reaction to the Commission's attempt last Friday - quickly reversed - to trigger Article 16 of the protocol due to new restrictions on the export of Covid-19 vaccines, is now being used as a pretext to mount a more aggressive assault on the protocol.
This has coincided with the DUP's five-point plan to get rid of the protocol altogether.
In his letter to Mr Sefcovic on Tuesday night, Mr Gove demanded sweeping and swift changes to the protocol, making an implicit link between the alleged intimidation at ports and what he depicted as wider public antagonisms towards the Protocol.
EU officials say the UK has yet to activate and utilise some of the flexibilities within the protocol that both sides agreed in December.
In an interview with RTÉ News last night, Mr Sefcovic said it would be better if the UK began implementing the flexibilities that were agreed just six weeks ago, rather than to begin a hard renegotiation of the protocol.
The Taoiseach has said that there are areas where the Northern Ireland Protocol can be fine tuned.
Speaking on RTÉ's Prime Time, Micheál Martin a common sense, pragmatic approach needed to be taken to iron out the issues around its implementation.
The Taoiseach said where tensions arise "we need to dial down the rhetoric" saying the protocol has only been five weeks in operation.
He said while he understood there is pressure on unionism because of the protocol, he believed it is a positive thing that will yield important dividends.
Meanwhile, Northern Ireland's First Minister said they were told that there was a need for the Protocol to prevent a hard border on the island of Ireland, but the "damage it would do" between Great Britain and Northern Ireland was not taken into consideration.
Speaking on RTÉ's News at One, DUP leader Arlene Foster said there is not only damage to trade, but to consumers as well.
She said: "Parcels are no longer being delivered, pets can no longer travel with their owners to Great Britain.
"We've had a situation where it was suggested that military equipment wouldn't be able to move with army personnel if they needed to come to Northern Ireland."
Ms Foster said the way forward is to look at the risk to the European single market.
She said: "If you take, for example, a ready meal that comes from a supermarket in Great Britain to Northern Ireland that is for sale in Sterling, there is absolutely no risk of that going into the EU's single market," she said. "So there is an absolute need to look at this in a constructive way."
She said ministers had taken "a considered approach" to ensure the people of Northern Ireland did not suffer any more than they already are.
Ms Foster said the "damage that has been done" by the protocol "far outweighs any benefits" for people in the north.
Earlier, Deputy First Minister Michelle O'Neill has called on Ms Foster and the DUP to "step back from the brink".
In an interview on RTÉ's Morning Ireland she said the DUP approach to the Northern Ireland Protocol is unrealistic and ironic, given the party were champions of Brexit, adding there is no sense of re-negotiating the protocol.
Michelle O'Neill says the DUP's approach to the Northern Ireland Protocol is unrealistic pic.twitter.com/mqcTvUEEOB
— RTÉ News (@rtenews) February 4, 2021
She said what we are dealing with now are the consequences of Brexit and the protocol gives protection to the Good Friday Agreement and protecting the all-island economy.
Ms O'Neill said the DUP needs to dial down the rhetoric and focus on finding solutions to the problems.
She acknowledged that there are teething issues but said that it "needs to be given more time" because it has only been in place for six weeks.
The DUP had rejected every other option that was presented to them, she added.
Elsewhere, Minister for Foreign Affairs Simon Coveney has said the Government wants to be helpful in solving problems around the protocol.
Speaking on BBC Radio Ulster's Good Morning Ulster programme, he said: "We want the protocol to function in a way that works for everyone, north and south on the island of Ireland."
Mr Coveney said the protocol was a result of Brexit and followed two years of negotiation.
He said the options were "narrowed significantly" in trying to find a solution mitigating the impact of Brexit on the island of Ireland.
He added: "The EU wanted to share a single market and customs union and that was turned down."
Additional reporting PA
