In a strongly-worded intervention, Ms Pelosi urged the UK and the EU to continue negotiations on the Northern Ireland Protocol to uphold peace in the region.
The congresswoman said in a statement: “The Good Friday Accords are the bedrock of peace in Northern Ireland and a beacon of hope for the entire world.
“Ensuring there remains no physical border between the Irish Republic and Northern Ireland is absolutely necessary for upholding this landmark agreement, which has transformed Northern Ireland.”
The comments from Ms Pelosi are a reminder of the concern over Northern Ireland at the highest levels in Washington, amid political instability following the Assembly election.
The Democratic Unionist Party (DUP) is currently blocking the re-establishment of Stormont’s power-sharing institutions in protest at the protocol, which has created economic barriers on trade between Great Britain and Northern Ireland.
“It is deeply concerning that the United Kingdom is now seeking to unilaterally discard the Northern Ireland Protocol. Negotiated agreements like the Protocol preserve the important progress and stability forged by the Good Friday Accords, which continue to enjoy strong bipartisan and bicameral support in the United States Congress,” Ms Pelosi said.
“As I have stated in my conversations with the Prime Minister, the Foreign Secretary and Members of the House of Commons, if the United Kingdom chooses to undermine the Good Friday Accords, the Congress cannot and will not support a bilateral free trade agreement with the United Kingdom.
“Respectful of the will of the British people and of Brexit, I urge constructive, collaborative and good-faith negotiations to implement an agreement that upholds peace.
“The children of Northern Ireland, who have never known the bloody conflict and do not want to go back, deserve a future free of the violence where all may reach their fulfillment.”
Ms Pelosi’s comments echoed a warning she made in person to Boris Johnson in Downing Street last year when she told him not to jeopardise the Good Friday Agreement.