The US is scheduled to host the World Championships for the first time in 2021 - in Eugene, Oregon - and the IAAF has asked for more information on the immigration order.

It said in a statement: "We clearly need to understand the implications of this new US immigration policy and will be seeking assurances that it will not adversely affect the IAAF World Championships in the USA in 2021."

On Sunday, Sir Mo Farah, who won the 5,000 metres and 10,000m double at the World Championships in 2011 and 2015, expressed his relief after the Foreign Office said Trump's order did not apply to UK nationals.

Farah, currently training in Ethiopia, is a British citizen but his ability to return to his family in the States was initially unclear because his country of birth, Somalia, was included on the banned list.

However, irrespective of birthplace, British nationals are exempt from Friday's order, according to the Foreign Office, and will be allowed to enter the States.

Farah will therefore be able to reunite with his family in Portland, also in Oregon and where they have been based for the last six years, once he has finished his training camp.

"Mo is relieved that he will be able to return to his family once his current training camp concludes, however, as he said in his earlier statement, he still fundamentally disagrees with this incredibly divisive and discriminatory policy," said a spokesperson for Farah.

The 33-year-old earlier in the day highlighted the situation many nationals born in one of the seven banned countries were facing.

He said in a statement issued on Facebook: "On January 1 this year, Her Majesty The Queen made me a Knight of the Realm. On January 27, President Donald Trump seems to have made me an alien.

"I am a British citizen who has lived in America for the past six years - working hard, contributing to society, paying my taxes and bringing up our four children in the place they now call home.

"Now, me and many others like me are being told that we may not be welcome.

"It's deeply troubling that I will have to tell my children that Daddy might not be able to come home - to explain why the President has introduced a policy that comes from a place of ignorance and prejudice.

"I was welcomed into Britain from Somalia at eight years old and given the chance to succeed and realise my dreams. I have been proud to represent my country, win medals for the British people and receive the greatest honour of a knighthood. My story is an example of what can happen when you follow policies of compassion and understanding, not hate and isolation."