Carrie Symonds, the girlfriend of UK prime minister Boris Johnson, has reportedly been refused entry to the United States for a planned visit.
Symonds had applied for permission to enter the country in the next few days as part of her role at Oceana, an environmental group.
The request was blocked by US officials, the Daily Mail reported, because of a previous visit to Somaliland.
The US does not recognise Somaliland as an independent country, categorising it instead as part of Somalia.
Symonds went to the country with her friend Nimco Ali, a campaigner against female genital mutilation. The visit included a meeting with self-declared Somaliland president Muse Bihi Abdi to discuss sea pollution and women's issues.
Symonds is now said to be in a race against time to get the visa.
It is unclear if Symonds applied for an Electronic System for Travel Authorisation (Esta).
An Esta is an automated system that decides if tourists can enter the US for 90 days without a visa as long they don't pose a security risk.
One question on the Esta form asks: "Have you travelled to, or been present in Iraq, Syria, Iran, Sudan, Libya, Somalia or Yemen on or after March 1, 2011?"
Answering yes could see the Esta application rejected.
Prime minister Johnson is due to meet Donald Trump at the G7 summit in France at the weekend.
Symonds has no official role in No 10 and no taxpayer-funded support, although she has been pictured at functions in Downing Street with Johnson.
A diplomatic source told the Daily Mail: "We are hopeful this can be sorted out in time for Ms Symonds to go to the US as planned."