The DUP has warned that North-South relationships cannot continue as normal and it will stop all cross-Border activity related to the Northern Ireland protocol.
Announcing a five-point plan to have the North “freed from the protocol” on Tuesday evening , the DUP said it intended to “send a strong signal to the Government of the Republic of Ireland that North-South relationships are also impacted by the implementation of a protocol which they supported.”
The party also intends to oppose all protocol-related measures in the North's Assembly and start an online petition to trigger article 16 of the protocol to secure "unfettered" trade between Great Britain and Northern Ireland.
The Irish Government said the protocol had been negotiated and agreed by the EU and the UK, and it would "work constructively with all parties in support of effective implementation of the protocol in a manner that meets its objectives, including through the structures and processes for engagement on and resolution of any issues that arise".
The DUP in its statement referenced threats which led to the withdrawal of staff carrying out post-Brexit checks at Belfast and Larne ports, saying that all political parties had rightly condemned these.
However, the party said “any unacceptable threats should not be taken into account as part of the equation, by either the UK government or the EU, as a reason not to deal with the protocol and the trade problems flowing from it.”
On Tuesday, the police in Northern Ireland said there was “absolutely no information” to substantiate or corroborate claims that loyalist paramilitary organisations were involved in threats or intimidation towards staff carrying out post-Brexit checks in the ports of Belfast or Larne.
Physical checks on products of animal origin were suspended at the ports after workers were withdrawn over concerns for their safety and wellbeing following graffiti referencing increasing tensions around the Northern Ireland protocol and describing port staff as “targets”.
However, documentary checks continued to be carried out as usual and it is understood there were no delays at the ports or impact on the supply chain.
Assistant Chief Constable Mark McEwan told reporters police were aware of a “single anonymous piece of information” which had been circulating and which caused “real concern towards staff and their employers”.
He would not give any further details, but said it was the police’s assessment that those responsible were “individuals or small groups”.
There was no evidence, he said, to substantiate claims information was being gathered about officials.
However Mr McEwan said he was concerned about tensions within the community and appealed for calm, saying “what we’re seeing is the outworkings of that . . . individuals or small groups of people are getting involved in incidents of graffiti or intimidation”.
Members of the North’s Assembly on Tuesday condemned the threats and called for “cool heads”.
"We have seen over the last number of weeks, both in the public media and also in social media, a situation that has perhaps been described as being heated up," said the Alliance MLA Stewart Dickson, adding he wanted "to hear this Assembly cooling all of that rhetoric".