Britain has demanded that the European Union agrees to rewrite a deal overseeing the post-Brexit trade involving Northern Ireland just a year after it was agreed with the bloc, a call immediately rejected by Brussels.

The European Commission has said it will seek "creative solutions" to difficulties in trade between Britain and Northern Ireland caused by Brexit, but will not renegotiate the Brexit deal on Northern Ireland.

Taoiseach Micheál Martin has tonight said that there are mechanisms in the Brexit Trade Agreement and Withdrawal Agreement for issues to be resolved with "goodwill from both sides".

He added that the EU stood ready to engage with the UK in relation to those issues.

Mr Martin said that a phone call he had with British Prime Minister Boris Johnson yesterday centred on the Northern Ireland Protocol.

He said: "The bulk of yesterday's discussion was on the protocol and today's command statement, and we've made it very clear in yesterday's call, and we've made it consistently very clear to the UK government.

"The mechanisms exist within the Trade Agreement and the Withdrawal Agreement for issues that need to be resolved, pertaining to the operation and implementation of the protocol, they can be resolved with goodwill on both sides."

The British government has indicated it is seeking a "standstill period" to negotiate major changes to the protocol.

The British minister with responsibility for relations with the EU, David Frost, has said that the protocol is not sustainable and that the UK government is seeking for existing grace periods on Northern Ireland to be maintained.

The Taoiseach said: "The British Government have indicated I understand now today, formally, that they're willing to give this significant engagement over the coming months.

"Our sense from the European Union all along, and I spoke to President von der Leyen on this on Friday, (is that) the European Union has always been ready to engage in a positive way.

"There has to be quid pro quo. There has to be engagement on both sides. The European Union stands ready to engage with the United Kingdom in relation to these issues."

Ireland will closely analyse British proposals to reduce trade frictions between Britain and Northern Ireland, but any solution must remain within the terms of a deal agreed with the EU last year, Minister for Foreign Affairs Simon Coveney has said.

"We will continue to encourage the UK to work in partnership with the EU to identify realistic solutions in a spirit of positive and constructive engagement," Mr Coveney said in a statement after the British government demanded a new deal.

"However, any solutions must take place within the framework of the protocol and the principles that underpin it," he added, referring to part of Britain's EU exit deal that Britain wants to change.

Minister for European affairs, Thomas Byrne, said the UK and the EU could not "spend the next few years negotiating" over the Northern Ireland Protocol.

He told BBC Radio 4: "I take the UK today at face value, I think they do want to do what they have set out to do, but I think they are also constrained by an agreement they have signed.

"But we can't spend the next few years negotiating - I think the people that would harm most of all is the people of Northern Ireland."

The Northern Ireland Protocol was part of the Brexit settlement, backed by Boris Johnson, that finally sealed Britain's divorce from the EU four years after voters backed leaving in a referendum.

Businesses in Northern Ireland say it is damaging trade, and some pro-British groups have protested at what they say is a weakening of ties with Britain, raising concerns about a return to the violence which plagued the province for three decades.

"We cannot go on as we are," Brexit minister David Frost told the British parliament.

He said London wanted a new "balance" to eliminate EU oversight of the accord, and that Britain already had the right to unilaterally deviate from parts of it.

European Commission Vice President Maroš Šefcovic was clear that the protocol could not be redrawn, saying Mr Johnson and Mr Frost had negotiated it.

"We will not agree to a renegotiation of the protocol," he said. "Respecting international legal obligations is of paramount importance."

The protocol addresses the biggest conundrum of the divorce: how to ensure the delicate peace brought to the province by Good Friday Agreement - by maintaining an open border - without opening a back door through neighbouring Ireland to the EU's single market of 450 million people.

It essentially requires checks on goods between the British mainland and Northern Ireland, which remains part of the EU customs area.

The EU has refused to amend the protocol, fearing goods could enter its single market across the border without meeting its regulatory standards.

"We will continue to engage with the UK, also on the suggestions made today," Mr Šefcovic said in a statement.

"We are ready to continue to seek creative solutions, within the framework of the protocol, in the interest of all communities in Northern Ireland."

Britain has already unilaterally extended a grace period reducing checks on shipments of chilled meat products. The EU later agreed it could apply through September to end a dispute dubbed the "sausage war".

US urges no unilateral action on NI Protocol

The US State Department has called on both sides to avoid unilateral action in negotiations relating to the Northern Ireland Protocol.

The department's spokesperson, Ned Price, said that the US supports a close relationship between the UK and the EU, and between all communities in Northern Ireland.

"We continue to encourage the parties to negotiate within existing mechanisms and to avoid unilateral action," Mr Price said.

He also said that US President Joe Biden has been unequivocal in his support for the Good Friday Agreement.

"We do and we have encouraged all parties to prioritise political and economic stability in Northern Ireland in the context of these discussions," he said.

US Congressman Brendan Boyle, Co-Chair of the Congressional EU Caucus, has accused the UK government of trying to evade its responsibilities under the protocol.

"Their latest statement and proposed changes just continue this trend and serve only to further destabilise Northern Ireland," Mr Boyle said.

"I am gratified that a strong bipartisan majority in Congress, as well as the Biden Administration, continue to support the Good Friday Agreement in all its dimensions, which includes no hard border on the island of Ireland," he said.

Meanwhile, US Congressman Richard Neal said: "The Northern Ireland Protocol was negotiated between the United Kingdom and the European Union to facilitate post-Brexit trade while protecting the peace and prosperity established by the Good Friday Agreement.

"I welcome continued engagement between the UK and the EU on ways to protect the gains made by that historic peace accord in all of its dimensions.

"I strongly encourage the UK and the EU to work together in a flexible and pragmatic manner in an effort to improve implementation of the Protocol and to make it work more effectively for all affected parties."

Richard Neal Statement on UK Proposed Approach on the Northern Ireland Protocol

Also today, Ways and Means Committee Chairman Richard E Neal said he welcomed the continued engagement between the UK and the EU on ways to protect the gains made by the historic peace accord.

"I strongly encourage the UK and the EU to work together in a flexible and pragmatic manner in an effort to improve implementation of the Protocol and to make it work more effectively for all affected parties."

Additional reporting: Brian O'Donovan