Foreign Secretary Boris Johnson is attending a major Washington DC conference aimed at countering the Islamic State terror group as Britain seeks to play down controversies over alleged spying.
Mr Johnson was not intending to use his US trip to revisit transatlantic tensions over accusations that British intelligence was asked by the Obama administration to monitor Donald Trump when he was running for president, sources suggested.
The Foreign Secretary is keen to concentrate on efforts to fight IS, which the Government calls Daesh, at talks with representatives of some 60 countries.
The Foreign Secretary is also meeting senior US officials including secretary of state Rex Tillerson.
The visit comes after a diplomatic incident was sparked when White House press secretary Sean Spicer mentioned claims that British security agency GCHQ had spied on Mr Trump at Barack Obama's request.
In a rare public comment GCHQ said the claims were "utterly ridiculous nonsense" which should be ignored.
London is said to be satisfied by assurances that White House officials will not repeat the allegations.
Brexit is also expected to feature during the visit, as the UK attempts to prepare the way for a US trade deal after withdrawal from the EU.
Mr Johnson will travel to New York on Thursday and chair a United Nations Security Council meeting on security in Somalia, famine and South Sudan.
The Foreign Secretary will also host a UN event on female empowerment around the world, aimed at giving women better access to schools, jobs and democracy.
On Monday, NSA director Admiral Mike Rogers insisted his organisation did not ask GCHQ to spy on Mr Trump during his bid for the White House.
Asked if President Trump making "baseless" claims against British security services damaged the close relationship between the two nations, Admiral Rogers said: "I think it clearly frustrates a key ally of ours."