The US administration has been urged to reverse a decision to abolish of the post of special envoy to the north.
The last person to hold the post was Senator Gary Hart but he was not replaced following a shake-up of the US’s diplomatic service in the wake of Donald Trump's election victory.
The US State Department confirmed earlier this month that the post had been "retired" and its responsibilities assigned to the Bureau of European and Eurasian Affairs.
But 25 members of the US Congress have written to the secretary of state Rex Tillerson urging him to reconsider abolishing the post.
The letter notes that "40 million Americans of Irish descent have begun to speak out on this issue" and claims the Good Friday Agreement was "one of America’s most successful foreign policy accomplishments in recent memory".
It has been signed by at least five Republicans as well as Democratic members of Congress and highlights the threat Brexit poses to the 1998 accord.
The first US special envoy to was Senator George Mitchell, who was appointed in 1995, while Richard Haass undertook the role during George W Bush's administration.
