Two participants were seen marching in the parade wearing black face paint and appeared to represent Cameroon as part of a section dedicated to the Confederations Cup.

One was wearing a black Afro wig and a Cameroon national shirt, while he was also carrying bananas.

The other wore a yellow Cameroon shirt and African-style headwear.

The parade itself, led by Sochi Mayor Anatoly Pakhomov, was celebrating the start of the city's beach season.

Concerns over potential racism at next year's World Cup in Russia have been reignited by the incident, which came prior to the start of the Confederations Cup on June 17.

Cameroon are due to face Germany at the Fisht Stadium Sochi, the host city of the 2014 Winter Olympic and Paralympic Games, on June 25.

FIFA have reiterated their zero-tolerance policy against racism and warned that it will "not be tolerated" inside stadiums.

"FIFA takes a firm, zero-tolerance stance against any form of discrimination, as enshrined in the FIFA statutes," the statement from world football's governing body read.

"We understand that one of the goals of the parade in Sochi was to celebrate the teams participating in the FIFA Confederations Cup. 

"However the displays you mention are inappropriate. 

"According to the anti-discrimination monitoring system, which will be in place at the FIFA tournaments in Russia, blackening of faces is considered discriminatory and will not be tolerated inside the stadiums."

In a statement, the Sochi City Government insisted they did not mean to cause offence during the parade.

"By no means did the carnival parade intend to insult anyone,” it said. 

“On the contrary, it was organised with the friendliest of goals in mind: to create a positive atmosphere. 

"We look forward to warmly welcoming the Cameroon national team and its fans, as well as the representatives of all other countries, during the FIFA Confederations Cup."

Russia has long stressed that racism will not be a problem at either the Confederations Cup or the World Cup in 2018.

However, there have been a number of racism-related incidents in previous years with players targeted with monkey chants and bananas.

Earlier this year, former Chelsea midfielder Alexei Smertin was put in charge of investigating football racism in Russia despite claiming in 2015 that it did not exist in the country.