Three Mexican athletes have been suspended from the Pan American Games in Brazil after they tested positive for doping.  A Brazilian volleyball player is also facing a suspension for a positive test.
  
The three Mexican athletes were not identified on Thursday.  Mexican Olympic officials also did not reveal the substance for which they tested positive.  The results came from a check of the delegation before it embarked for Rio de Janeiro.

Meanwhile, Brazilian volleyball player Jacqueline Carvalho tested positive for a stimulant (sibutramine).  The substance is often used in weight-reduction medicine.  The test was conducted on June 10 in Cologne, Germany after the finals of the Italian league volleyball championship.  Carvalho plays for the Italian team Monte Schiavo Banca Marche Jesi.

The Pan American Games opening ceremonies take place Friday night at Maracana Stadium in Rio De Janeiro.  More than 5,500 athletes from 42 nations and territories are taking part in this Western Hemisphere Olympics-like competition.  It runs through July 29.

Some information for this report was provided by AP.