Two Mali footballers Mohamed Camara and Sekou Koita were handed three-month doping suspensions on Thursday.
The ban means they will not be available for the already-qualified Mali’s final two Africa Cup of Nations qualifiers against Guinea and Chad next month.
According to their Austrian club Red Bull Salzburg the pair had taken altitude sickness medicine while on international duty.
Salzburg said the pair were positive for a banned substance in a Uefa drugs test carried out on 22 November last year.
“Mohamed Camara and Sekou Koita are to be suspended for three months. This suspension is effective immediately and covers all club and international football activities,” the 14-time Austrian champions announced.
“In its verdict, UEFA ruled that in this case there was no intentional violation of doping rules, but the rules stipulate that every player is personally responsible for ensuring that no banned substances enter their body, which occurred for Camara and Koita during international action for Mali.”
Midfielder Camara and striker Koita, both 21, said they had been treated by the Mali team doctor before playing an Africa Cup of Nations qualifier in the Namibian capital of Windhoek which sits at 1,700m above sea level.
“They received a medicine to combat altitude sickness that contained a substance on the banned list. The doctor responsible was immediately suspended by the Mali football association,” added the club.
Koita said on Twitter he was “sad” but “relieved to see that UEFA had heard and taken into account all the elements of the file”, and urged the young players to “be extremely careful with products distributed by medical staff”.