US president-elect Joe Biden has stressed the importance of keeping the Irish border open following Brexit.

Speaking to reporters in Wilmington, Delaware, on Tuesday, he said: “We do not want a guarded border. We want to make sure – we’ve worked too long to get Ireland worked out, and I talked with the British prime minister, I talked with the Taoiseach, I talked with others, I talked to the French.

“The idea of having a border north and south once again being closed is just not right, we’ve just got to keep the border open.”

Mr Biden discussed Brexit with Prime Minister Boris Johnson earlier in November during one of his first phone calls to other world leaders as president-elect, warning him Brexit must not jeopardise the Northern Ireland peace process.

Mr Biden previously touched upon the 1998 Good Friday agreement during his presidential campaign, tweeting in September: “We can’t allow the Good Friday Agreement that brought peace to Northern Ireland to become a casualty of Brexit.

“Any trade deal between the US and UK must be contingent upon respect for the Agreement and preventing the return of a hard border. Period.”

A Northern Ireland Office (NIO) minister reiterated the Government’s position.

Robin Walker said: “There will be no border post. I think what president-elect Biden was setting out is a shared ambition for the UK Government, for the Irish and indeed for the US, that there should be no guarded border between Northern Ireland and the Republic of Ireland.

“That is something that we are all absolutely committed to delivering on under all the circumstances envisaged from the outcome of the negotiations.”

He told MPs on the Northern Ireland Affairs Committee that the US had a great interest in Northern Ireland and was a key investor.

Trade negotiations between the UK and EU are continuing, although time is running short for a deal to be reached and ratified before the current transitional arrangements expire at the end of the year.

European Commission president Ursula von der Leyen told MEPs the talks were in “decisive days”, adding: “I cannot tell you today if, in the end, there will be a deal.”

There had been “genuine progress” in some areas, with the outline of a “possible final text” in areas including criminal justice, goods and services and transport.

But there have been no breakthroughs in the three areas which have proved problematic for months – fishing rights, governance of any deal and the “level playing field” designed to prevent unfair competition on standards and state subsidies.

Ms von der Leyen said “with very little time ahead of us” the EU was “ready to be creative”, but it would protect the integrity of the single market.

There were still “serious issues” around state aid and the possibility of the UK drifting away from EU standards on labour and environmental standards.

Mr Johnson has insisted he will not sign up to anything which ties the UK to EU rules, but Ms von der Leyen said: “We want to know what remedies are available in case one side will deviate in the future because trust is good, but law is better.”

Ulster Unionist leader Steve Aiken said nobody wanted to see a guarded Irish border or one in the Irish Sea between Northern Ireland and the rest of the UK.

“It should also be remembered why a ‘guarded border’ was there in the first place and it was to protect Northern Ireland’s citizens from a vicious terrorist campaign being waged by the IRA while the Republic of Ireland was being used as a launchpad for numerous indiscriminate shootings and bombings.

“I would ask that the incoming Biden administration focuses on the content of what’s actually in the Belfast Agreement.

“A border down the Irish Sea poses an existential threat to the Agreement itself.

“This has been repeatedly ignored by the Irish Government and it’s about time that they started respecting the Agreement rather than using it as a weapon during Brexit negotiations.”