A US delegation, led by Congressman Richard Neal, is to meet Stormont's five main parties today.
The US Congressional Ways and Means Committee delegation has held a number of meetings over the past numbers of days, with the issue of the Northern Ireland Protocol being the main topic raised.
The visit has been contentious among unionists, with DUP leader Jeffrey Donaldson calling the "terrible."
"Since Neal set foot on these shores, he has once again demonstrated a one-sided approach to Northern Ireland and exposed either an incredible lack of understanding or a dangerous willingness to misrepresent reality."
Neal this week told reporters in Dublin that the issue over the protocol was "manufactured," with Donaldson saying "there is nothing 'manufactured' about the Protocol problems."
"This was an outrageous comment for such a senior US politician to make. Whether it is our pharmacies accessing medicines, our garden centres buying plants, farmers unable to move livestock, manufacturers unable to bring in parts or our supermarkets seeing the price of frozen food forced up, the Irish Sea border is real and is having a costly impact on everyone in Northern Ireland."
Donaldson described the visit as "more of a hinderance than a help."
"Despite the one-sided approach of Rep Neal, we will be attending the meeting to put forward our view to his delegation. I am a firm believer in challenging those who have adopted a Sinn Féin narrative. I have challenged Congressman Neal and others before and I will continue to do so.”
Ulster Unionist Party leader Doug Beattie similarly said that for Neal to suggest the issues around the Protocol are manufactured "demonstrates a lack of understanding of the damage which the Protocol is doing and that he is somewhat removed from the reality of the situation."
Neal also used the term 'Planter' in an interview on RTÉ about the Good Friday Agreement, referring to those who came to Ireland during the Planation of Ulster in the 1600s.
"His thinking and terminology are of a time past," Beattie said. "We have friends in the United States which we need to engage with more and Congressman Neal's biased view of the past and the present, are not representative of American diplomacy.
On Wednesday night, the American delegation was hosted by NI Secretary Brandon Lewis, who said the UK and the US were united in their shared commitment to the Good Friday Agreement.