Five Mexican internationals currently taking part in the Gold Cup tournament were suspended Thursday for doping, the secretary general of the country\'s football federation (Femexfut) announced. Goalkeeper Guillermo Ochoa, who plays for the Mexican side America, defenders Francisco Javier Rodriguez of Dutch side PSV and Edgar Duenas of Mexico\'s Toluca and midfielders Antonio Naelson of Toluca and Christian Bermudez of Atlante tested positive for the banned drug clenbuterol. \"From now we\'ll go through a very difficult period which will see the players separated (from the Gold Cup team) and an inquiry opened,\" said Femexfut secretary general Decio de Maria, who said it was too early to assign blame. \"It\'s an unpleasant and difficult moment but we have to respect the rules.\" The positive tests came on May 21 when the team was assembled for a training camp ahead of the Gold Cup, the CONCACAF regional championship which defending champion Mexico opened last Sunday with a 5-0 thrashing of El Salvador. \"Something in the food on May 18, 19, 20, something in the chicken or beef that the team ate was contaminated with clenbuterol,\" De Maria theorized. \"We suspect something in training camp. It\'s hard to know exactly what would make five players from different clubs test positive when the team is natural.\" Mexico were set to face Cuba later Thursday in Charlotte, North Carolina, in their match in the 2011 Gold Cup regional championship. CONCACAF secretary general Chuck Blazer told ESPN radio from the governing body\'s headquarters in New York that the Gold Cup competition committee would meet on Friday to discuss whether Mexico could replace the five players for the remainder of the tournament. CONCACAF confirmed that Mexico\'s opening Gold Cup victory over El Salvador would stand. While de Maria said suspending the players provisionally was necessary, he insisted that the real circumstances of the cases remained to be determined. Spanish cyclist Alberto Contador, a three-time Tour de France champion, tested positive for clenbuterol during the 2010 Tour but said he had unknowingly consumed drug-contaminated meat.