US President Joe Biden will later tell PM Boris Johnson not to let the row over post-Brexit trading in Northern Ireland affect the peace process.
The two leaders will have their first face-to-face talks in Cornwall on the eve of the G7 summit.
Mr Biden will stress the need to “stand behind” the Northern Ireland protocol.
They will also discuss transatlantic travel and a new “Atlantic Charter” aimed at refreshing the so-called “special relationship”.
The US President is on his first overseas visit since being elected and the G7 summit is the first time world leaders have all gathered in person since the pandemic began.
The rollout of the coronavirus vaccination programme and climate change are high on the agenda.
But the dispute between the UK and the EU over regulatory checks on goods going in to Northern Ireland from Great Britain is also likely to feature heavily in diplomatic discussions in the coming days.
President Biden has a close interest in Ireland, given his ancestral roots, and had warned that the Good Friday Agreement must not be jeopardised by rows over trade.
Business and political leaders in Northern Ireland have warned that the trade dispute is causing political angst and instability in the run up to the marching season next month.
Talks on Wednesday between Brexit minister Lord Frost and the European Commission’s Maros Sefcovic ended without a breakthrough.
Mr Sefcovic said the EU was running short of patience with the UK’s attitude towards the protocol, after UK ministers said they were prepared to ignore parts of it to prevent disruption to supplies of food and other goods to Northern Ireland from Great Britain.
In a press conference on Thursday morning, European Commission president Ursula von der Leyen said the protocol was the “only solution” to prevent a hard border with the Republic and must be implemented “completely”.
Mr Johnson said on Wednesday that resolving the dispute with Brussels was “easily doable” and “what we want to do is make sure that we can have a solution that guarantees the peace process, protects the peace process, but also guarantees the economic and territorial integrity of the whole United Kingdom”.
But Labour’s shadow Northern Ireland Secretary, Louise Haigh has accused the prime minister of “inflaming” tensions in Ireland.
She said: “It is worrying on the eve of such an important summit that Boris Johnson’s actions are isolating Britain from our strongest allies.
“The prime minister personally negotiated the protocol so has a responsibility to make it work, and protect the precious Good Friday Agreement.”
Source: BBC
