The US embassy in London appeared to directly contradict a statement by the foreign secretary this morning, by issuing a notice people who have dual nationalities with countries on Donald Trump's banned travel list not to apply for a US visa.
In a statement posted on the embassy's website this morning, it advised: "If you are a national, or dual national, of one of these countries [on Trump's list], please do not schedule a visa appointment or pay any visa fees at this time".
The statement came after Trump signed an executive order over the weekend banning people from Iraq, Iran, Libya, Somalia, Sudan, Syria and Yemen from travelling to the US.
The order resulted in hundreds of travellers being detained at US airports or prevented from travelling altogether.
Last night Boris Johnson reassured Britons with dual citizenship, saying those who share nationality with one of the nations on the list will be exempt from the ban.
In a statement the foreign office said the order "only applies to individuals travelling from one of the seven named countries", adding: "If you are a dual citizen of one of those countries travelling to the US from OUTSIDE those countries then the order does not apply to you". It is thought the advice came from Trump's administration.
Politicians responded to the ban over the weekend, with Sadiq Khan calling it "shameful and cruel".
"The USA has a proud history of welcoming and resettling refugees. The President can't just turn his back on this global crisis - all countries need to play their part," he said.
Meanwhile, a petition calling for a state visit to the UK by Trump to be cancelled has reached more than a million signatures.
The Foreign Office and the US embassy have been contacted for comment.