US President Joe Biden has reiterated his warning that peace in Northern Ireland must not be jeopardized by post-Brexit rules-related tensions.

Biden’s warning came during an Oval Office meeting with UK Prime Minister Boris Johnson.

He underlined the importance of balance in the region, which was established by the 1998 Belfast (Good Friday) Agreement.

-I feel very strongly - he responded to a question about the Northern Ireland protocol. - We spent an enormous amount of time and effort in the United States. It was a major partisan effort, and I would not like to see – nor would many of my Republican colleagues – a change in the Irish accord.-

In response, Johnson said the UK is “completely at one, because nobody wants to see anything that interrupts or unbalances the Belfast or Good Friday Agreement.”

Biden, who has got Irish roots, has repeatedly warned that peace in Northern Ireland should be kept and the Good Friday Agreement must be preserved.

Last week, US House of Representatives Speaker Nancy Pelosi had warned the UK that a possible US-UK trade deal will be jeopardized if disagreements with the EU, which threatens peace in Northern Ireland, are not eliminated.

Dozens of police officers were injured, public buses and cars were damaged during riots by the loyalist groups in Northern Ireland earlier this year.

The loyalists argue that the Northern Ireland Protocol, which aligns the region with the EU in a bid to avoid a hard border in the island, created a de facto border between Northern Ireland and rest of the UK, imposing a border check on goods between Great Britain and the region.

In a recent address, Democratic Unionist Party leader Jeffrey Donaldson outlined his willingness to bring down the Stormont (Northern Ireland Assembly) if the protocol is not changed substantially.

Northern Ireland voted to remain in the EU in a 2016 referendum, but it is feared the Brexit process could trigger enmity in the region.

The Troubles – an era of conflict between the British government and pro-British paramilitaries on one side, and Irish Republicans and nationalists on the other – ended in 1998 when the Belfast Agreement put an end to decades of armed struggle in the divided UK region of Northern Ireland.

The UK and the Republic of Ireland signed the deal, brokered by the US and eight political parties in Northern Ireland, on April 10, 1998.

The deal, dubbed the Good Friday Agreement, largely saw the end of the Troubles-era violence, in which 3,500 people lost their lives.