The secretary of state, Mike Pompeo, has said that the US will be "on the doorstep, pen in hand", ready to sign a new trade deal with the UK as soon as possible after Brexit.
Pompeo was speaking alongside Dominic Raab, who was making his first trip to Washington as UK foreign secretary. Raab restated the British government's determination to leave the EU at the end of October, and claimed that Donald Trump, whom he met at the White House on Tuesday evening, "was effusive in his warmth for the United Kingdom".
"It was amazing to hear an American president talk about our country in such warm terms," the foreign secretary said, adding that there was "huge appetite on both sides" for achieving a deal.
"Of course, America is our single largest bilateral trading partner," Raab said. "President Trump has made clear again that he wants an ambitious free trade agreement with UK. So I hope we can make that happen as soon as possible after we leave the EU on 31 October."
After meeting with Raab on Wednesday at the state department, Pompeo said: "We support the United Kingdom's sovereign choice, however Brexit ultimately shakes out. And the we'll be at the doorstep, pen in hand, ready to sign a new free trade agreement at the earliest possible time."
He said he was confident that the manner of the UK's departure from the EU would safeguard the principles of the Good Friday agreement in Northern Ireland.
A no-deal Brexit without any resolution to what would happen to the border between the two Irelands is likely to jeopardise the 1998 peace agreement, which relies on the unrestricted flow of people and goods.
Any US trade deal with the UK would have to be approved by Congress and the Democratic leadership. It would also need approval from the Irish American Republicans in the House of Representatives who have warned that they would block a deal if Brexit affects the Irish border, and therefore the Good Friday peace agreement.
In the Senate, 45 Republicans have signed a letter pledging unconditional support for a US-UK trade deal, but that falls short of a majority the administration will need to get an agreement through the upper chamber.
Pompeo thanked the UK for its decision to join a US-led maritime protection force in the strait of Hormuz, to defend oil tankers following the Iranian seizure of a British-flagged vessel, the Stena Impero.
"This is a victory for meaningful, effective multilateralism," he added. Pompeo also expressed US gratitude for "contributions towards alleviating Iranian-caused suffering in Yemen".
"We hope the UK will keep taking new steps to hold the Islamic Republic of Iran responsible for its rash of destructive behaviour," the secretary of state said.
Raab, however, made clear the UK upheld its commitment to the 2015 nuclear deal with Iran, which the Trump administration abandoned in May last year.
"We continue to want to make the deal work, and more broadly..de-escalate tensions so far as we can," he said.