Britain on Tuesday condemned threats to port workers implementing controversial post-Brexit trade checks in Northern Ireland, calling for clear heads to ease fears of an upsurge in sectarian tensions but pointing blame at the European Union.
Checks were suspended at Belfast and Larne ports late Monday, and the European Commission said it had told its staff working at two border posts in the British province to stay away.
The development comes just over a month into new trading arrangements after Brexit took full effect, and warnings it could stoke lingering community tensions in Northern Ireland.
Prime Minister Boris Johnson said EU moves last week to restrict vaccine exports to the UK province, amid controversy over jab deliveries but which were swiftly abandoned, had "undermined" its special post-Brexit arrangements and "provoked concern".
"What is needed is urgent action from the EU to resolve outstanding problems with Protocol implementation," he said on Twitter, while reiterating "Northern Ireland's place in the UK will be protected and strengthened".
Earlier, senior UK minister Michael Gove had told British lawmakers it was vital "that everyone in Northern Ireland, and indeed the rest of the UK, exercises calmness and moderation as well as resolution to resolve the problems".
He called the threats "completely unacceptable", echoing condemnation from the power-sharing Northern Ireland executive and the European Commission.
- 'Individuals or small groups' -
The regulatory animal-based food checks were dropped on the orders of Northern Ireland's Department of Agriculture, Environment and Rural Affairs.
At Larne Port, 12 staff were pulled from duties after "an upsurge in sinister and menacing behaviour in recent weeks", the Mid and East Antrim Borough Council said.
Hardcore unionists have been blamed for graffiti criticising the Northern Ireland Protocol and describing port staff as "targets", it added.
Attempts also seemed to have been made to collect information on employees, including vehicle registration plates, in acts of intimidation recalling the darkest days of "The Troubles" in Northern Ireland, media reported.
But officers are said to have no evidence that intimidation efforts are being organised by the main loyalist paramilitaries active in the province.
Police Service of Northern Ireland (PSNI) Assistant Chief Constable Mark McEwan told the BBC that "individuals or small groups of people" were responsible.
Lorries were still passing through the port at Larne, but police patrols have nevertheless been stepped up, while Northern Ireland's leaders are due to talk to UK and EU ministers on Wednesday.
- 'The Betrayal Act' -
The Northern Ireland Protocol came into effect on January 1, when the Brexit transition period ended and Britain's 2016 vote to split from the EU came into full effect.
It is designed to prevent a hard border emerging between the north and EU member Ireland -- a frequent flashpoint in three decades of violence over British rule.
Up to 1998, some 3,500 people were killed as unionists who back ties to Britain engaged in a deadly tug-of-war with republicans seeking to merge the province with Ireland.
Security checkpoints and patrols along the 500-kilometre (310-mile) border were targeted by republican paramilitaries in some of the bloodiest chapters of the sectarian violence, with fears of a possible post-Brexit return.
The protocol avoids the need for a potentially troublesome hard border by transplanting EU single market and customs union checks to Northern Irish ports and airports.
But it drew unwelcome attention last weekend after the row over coronavirus vaccines pushed the European Commission to warn it would invoke "Article 16" of the treaty.
The fallback provision allows London or Brussels to unilaterally suspend aspects of the deal in special circumstances.
Although Brussels quickly backtracked on the threat following criticism from the UK, Ireland and all of Northern Ireland's mainstream political parties, it renewed unionist ire.
They believe the protocol creates a de facto "sea border" between Northern Ireland and mainland Britain and binds the province in an economic union with EU member Ireland.
Unionists -- and more hardcore loyalists sometimes linked to paramilitaries -- branded 2019 legislation to enact the protocol "The Betrayal Act".
Last week, the PSNI's McEwan said police officers were noticing "growing discontent" among the unionist community -- chiefly manifested by graffiti and on social media.