America will not negotiate a new trade deal with Britain until the UK's future relationship with the European Union becomes clearer.
US Trade Representative Michael Froman said on Monday that the two countries cannot launch negotiations on bilateral trade and investment deals until more is known about any newly-shaped agreement between Britain and Europe.
Speaking to British counterpart Liam Fox, Mr Froman said the "United States will be prepared to engage in conversations with the United Kingdom about how to develop our trade and investment relationship in the best way at the appropriate time".
Last week, Prime Minister Theresa May told German Chancellor Angela Merkel that the UK would not rush its exit from the EU.
Britain voted in a referendum to leave the European bloc over a month ago.