FIFA's leadership has written to World Cup teams urging them to focus on the tournament in Qatar and not be part of lecturing on morality and dragging football "into every ideological or political battle that exists".

Sky News has exclusively seen the full letter from FIFA's president, Gianni Infantino, and the governing body's secretary general, Fatma Samoura, that has been sent amid growing pressure on players to be activists around the tournament.

It has been a World Cup build-up dogged by concerns about the suffering of low-paid migrant workers to build the infrastructure in the tiny Gulf nation and discriminatory laws that criminalise same-sex relations.

"Please, let's now focus on the football!" Infantino and Samoura wrote to the 32 football nations contesting the World Cup.

"We know football does not live in a vacuum and we are equally aware that there are many challenges and difficulties of a political nature all around the world.

"But please do not allow football to be dragged into every ideological or political battle that exists."