Senegal have accused Watford of refusing to release Ismaila Sarr for the Africa Cup of Nations later this month.
The 23-year-old was selected as a part of Senegal squad despite being sidelined with a knee injury he sustained in November.
The Senegal Football Federation have described Watford's alleged actions as 'disrespectful, pernicious and discriminatory'.
'By mail on Friday, December 31, the English club Watford notified on the basis of arguments equally specious as fallacious its decision to block the player Ismaila Sarr, who has expressed his desire to join the Senegalese selection for the next Cup of Nations in Cameroon,' said a Senegal Football Federation (FSF) statement.