Brexit should be just an “aberration” in the bid to strengthen Northern Ireland's peace process, US congresswoman Nancy Pelosi has said.
The US House of Representatives Speaker has visited the Irish border which has become a stumbling block to the UK’s EU withdrawal.
She was greeted by anti-Brexit campaigners during her short stop at the frontier on Thursday.
The senior Democrat from California said the US had a vested interest in peace in Northern Ireland which was sealed by the 1998 Good Friday Agreement.
Ms Pelosi repeated her assertion that the peace process was a “beacon to the world” and a model for reconciliation.
She said: “Far be it for any of us to want that beacon’s lustre to be dimmed by anything that the Brexit conversation could bring down on the Good Friday accord.”
The congresswoman walked across the peace bridge over the River Foyle in Londonderry.
It was built using EU funds and links primarily nationalist and primarily unionist communities on either river bank.
Ms Pelosi said her border visit was made out of respect for the courage of those who participated in the Good Friday accord.
Earlier this week, she warned that US trade talks with the UK could be endangered if the agreement which largely ended decades of violence was compromised.
John Boyle, Mayor of Derry City and Strabane Council, said it was evident Ms Pelosi was determined to protect the integrity of the agreement.
“They will support us in ensuring it does not impact on that very important agreement which was signed in 1998,” he said, adding that a hard border would be difficult to deal with psychologically.
“Many of us going back generations remember what a hard security border looked like here.”