US President Donald Trump on Monday backed FIFA president Gianni Infantino, who is in hot water over allegations of a workplace affair and criticism of a failed private investment scheme.

"FIFA would be making a terrible mistake if, for any reason, they even considered replacing President Gianni Infantino," Trump said in a Truth Social post, calling the Italian-Swiss lawyer "fantastic" and saying he "presided over the most successful World Cup, by four times, ever presented."

"If he is gone, it will never be as successful or profitable again!"

Trump's backing of Infantino contrasts with the response of US Soccer, which issued a statement critiquing the FIFA leader alongside Canada Soccer and football organizations in Central America and the Caribbean.

Infantino, who faces reelection next March, has denied allegations of wrongdoing, and FIFA for their part has backed its beseiged president, calling the backlash "a concerted and ongoing effort by some to undermine" the organization.

Other football organizations, including the Confederation of African Football and South American governing body CONMEBOL, share Trump's position in supporting Infantino.

© Agence France-Presse