THE former Brexit minister has accused the US administration of not fully understanding Northern Ireland and the impact of the Northern Ireland Protocol.
Lord David Frost also told US President Joe Biden that the UK doesn’t need "lectures from others" about the Good Friday Agreement.
It comes just days after the US government had intervened in the protocol row and urged the British Prime Minister Boris Johnson not to rip it up.
"The best path forward is a pragmatic one that requires courage, co-operation and leadership," a White House spokeswoman said.
"We urge the parties to continue engaging in dialogue to resolve differences and bring negotiations to a successful conclusion."
Lord Frost, who resigned from the UK government over "concerns about the current direction of travel" in December last year, said he was aware that the Biden administration was paying close attention to the way the UK government is dealing with the protocol issue".
"I'm not convinced the niceties are well understood," he told a leading Conservative think-tank in Washington DC.
"I get slightly frustrated when we are told by a third party, albeit a very important one in this context, how to manage these issues.
"It is our country that faced terrorism, faced the Troubles. I am old enough to remember having to check under my car every morning, as a diplomat, before I went to work. Most people were very affected in one way or another by this.
"So we don't need lectures from others about the peace process and the Good Friday Agreement. We are well aware of this and nobody wants to go back to it. In the end it has got to be our judgment about what is needed to preserve that agreement and preserve the unity of the country and the consent of everybody in Northern Ireland for these arrangements."
