The European Commission Vice-President has said he will meet the UK's Brexit Minister David Frost again next week after holding talks in London today.

In a tweet, Maroš Šefčovič said he met Mr Frost to discuss the EU's proposed solutions to facilitate the implementation of the Northern Ireland Protocol.

Meanwhile, the EU's chief Brexit negotiator has told member states there is a clear link between the bloc's free trade deal with Britain and the Northern Ireland Protocol, RTÉ News understands.

Maroš Šefčovič referred to Britain’s continuing threats to trigger Article 16 and said the Trade and Cooperation Agreement was contingent on the sequencing in the divorce negotiations, which included resolving the Irish border issue first.

"That sequencing could be endangered depending on how Article 16 was triggered," said one source present at the meeting.

"So, while [Šefčovič] didn't explicitly promise to say or do anything [if Article 16 were triggered], he did raise that link. He pointed it out."

In a downbeat assessment of the ongoing technical talks between the EU and UK, Mr Šefčovič told EU ambassadors in Brussels that the European Commission would formally set out its options to member states next week on how it should respond to a triggering of Article 16.

Talks have been under way for four weeks on a set of EU proposals designed to make the protocol more manageable for citizens, business and stakeholders in Northern Ireland.

The proposals cover the circulation of medicines, customs, agrifood checks and controls, and an enhanced oversight role for Northern Ireland institutions and businesses.

It comes as the President of the European Commission, following a meeting with the US President in Washington DC, told reporters "we share the assessment that it is important for peace and stability on the island of Ireland to keep the withdrawal agreement and the protocol".

Maroš Šefčovič has been in talks with the UK for the past four weeks

Mr Šefčovič, a vice-president of the European Commission, said that technical teams on both sides had attempted to develop a paper that would set out areas of common agreement.

However, he said that his UK opposite number, David Frost, had been reluctant to give the paper political backing.

Mr Šefčovič is said to have emphasised that the EU would continue to, as he put it, speak directly to the concerns of people in Northern Ireland.

He told ambassadors he would have further talks with Northern Irish businesses and stakeholders tomorrow.

A number of ambassadors are understood to have called for a "calm, methodical and proportionate" response if the UK triggers Article 16.

However, France and Germany both signalled that a robust response should follow.

It is understood Ireland told the Brussels gathering that no matter what emerged in the talks, the EU should ensure that it would always be possible to "return to the full implementation of the protocol, and that we shouldn't do anything that will be irreversible, or make a return to the protocol impossible".

Meanwhile, Northern Ireland was discussed when Ursula von der Leyen and Joe Biden met at the White House in Washington DC today.

Ursula von der Leyen and Joe Biden in the White House today

The President of the European Commission told reporters: "We share the assessment that it is important for peace and stability on the island of Ireland to keep the withdrawal agreement and the protocol."

Ms von der Leyen said the EU has shown the "utmost flexibility" within the protocol but it was "important to stick to what we have agreed and signed together to work with that".

Also today, Mr Frost said the EU should stay calm and avoid embarking on "massive and disproportionate retaliation".

Mr Frost said more talks would be held with the EU as the UK and the bloc struggled to overcome differences over the protocol.

But he told the British House of Lords in Westminster that triggering Article 16 would be the UK's only option if the dispute was not resolved.

"They seem to be claiming that it will be entirely unreasonable for the British government uniquely to use these wholly legitimate safeguard provisions ... they're also suggesting that we can only take that action at the price of massive and disproportionate retaliation," he said.

"I gently suggest that our European friends should stay calm and keep things in proportion."

Article 16 of the protocol allows either side to unilaterally suspend elements of the deal if it creates serious economic, societal or environmental problems.

The arrangement effectively keeps Northern Ireland inside the EU's single market for goods, resulting in some checks on products crossing the Irish Sea from Britain.

Taoiseach Micheál Martin has called for "dialogue and engagement" between the European Union and the UK to resolve long-running issues surrounding the protocol.

He told the Dáil, amid growing concerns that the UK government is about to trigger Article 16, that "discussions are still ongoing".

He added: "I would sound a note of caution that we don't automatically assume that anything is going to be triggered. I think that is important - that we don't fall into a self fulling prophecy."

Mr Martin said he did not think there was a need to trigger Article 16.

"Trade would be disrupted ultimately. Access to the single market is important to people in Northern Ireland. Any triggering of Article 16 could ultimately jeopardise, in the shorter term, that access," he told TDs.

The issue was raised in the Dáil by Labour leader Alan Kelly, who said "the last thing collectively we all need" is for a trade war to erupt between the EU and the UK, should Prime Minister Boris Johnson trigger Article 16.

Sinn Féin leader Mary Lou McDonald said the "vast vast majority of people from all communities" in Northern Ireland support the protocol and do not want to see the triggering of Article 16.

Members of US Congress call on UK to abandon 'dangerous path' on NI Protocol

Senior members of the United States Congress have called on the British government to commit to implementing the Northern Ireland Protocol in full.

In a statement, the members described the protocol as critical for ensuring Brexit does not undermine decades of progress toward peace on the island of Ireland.

"In threatening to invoke Article 16 of the Northern Ireland Protocol, the United Kingdom threatens to not only destabilise trade relations, but also that hard earned peace," according to the statement.

"We call on the UK to abandon this dangerous path, and to commit to implementing the Northern Ireland Protocol in full."

Triggering Article 16 'a bombastic move' - Hain

The statement was issued by US Representatives Gregory Meeks, Chair of the House Foreign Affairs Committee, William Keating, Chair of the Europe, Energy, the Environment and Cyber Subcommittee, Earl Blumenauer, Chair of the Ways and Means Subcommittee on Trade, and Brendan Boyle, Chair of the European Union Caucus.

The Minister for Foreign Affairs said that unilateral moves to suspend parts of the protocol would be viewed in US political circles as a "risk to political stability in Northern Ireland".

Speaking at the COP26 summit in Glasgow, Simon Coveney said: "There's a big US delegation here. They have very strong views on this issue.

"You know, on Capitol Hill and in the White House, in many ways, they see themselves as g uarantors or protectors of the Good Friday Agreement ... [and] so the triggering of Article 16, I think, is seen as a as a risk to political stability in Northern Ireland."

Additional reporting: Paul Cunningham, Brian O'Donovan, PA, Reuters