In a statement criticising the conduct of the club, the FSF claimed Watford had provided "spurious" reasons for denying Sarr permission to travel to Cameroon to represent Senegal at the tournament, which begins on Friday (January 7).

The FSF hit out at what it believes is "disrespectful, pernicious and discriminatory behaviour" by Watford over its treatment of the player and threatened to take its grievance to FIFA.

Watford responded by insisting the 23-year-old, capped 40 times by Senegal, was not fit after suffering an injury during their 4-1 win over Manchester United in November.

The club also said it had invited the FSF "to instruct their own independent surgeon to confirm the diagnosis and rehabilitation period" regarding Sarr's injury.

"Ismaïla Sarr suffered a knee ligament injury on 20 November in the match against Manchester United and has not been fit to play for Watford since," Watford said.

"In early December, the club wrote to the Senegal Football Federation outlining the clinical diagnosis of Ismaïla’s injury and immediately followed that up by supplying the MRI scans detailing the extent of the injury. 

"After further consultation with medical experts, we informed the federation of Ismaïla's rehabilitation process and likely timeframe of recovery.

"Within the past 10 days, the club has reiterated to the Senegal Football Federation the player's current medical status and recovery schedule."

The statement came after the FSF had expressed "deep condemnation of the disrespectful, pernicious and discriminatory behaviour of Watford who seek by all means to prevent a player from playing with his national team".

"Africa, its football and its footballers deserve the same respect as that accorded to other continents, Confederations and players," the FSF added. 

"The FSF will take all the necessary action to ensure that the basic right of its footballers to play for their country is respected."

It is the second time Watford have been at the centre of a row over the release of a player for the postponed Africa Cup of Nations.

The club also refused to release Nigerian striker Emmanuel Dennis, Watford's top scorer so far this season with eight league goals, for the tournament.

It claimed the Nigerian Football Federation had missed the deadline to inform the club of his selection, but the NFF said Watford were "baring fangs" when deciding not to allow him to travel to the event.