Mamadou Sakho has been stood down from first team action by Liverpool after the defender failed a drug test.

The France defender has been cited for taking something which is on UEFA’s banned substance list and although he is still eligible to play, the club have decided he will not be available for selection while an investigation is ongoing, but stress that he has not been suspended.

In a statement on the club’s website, Liverpool confirmed that they are “investigating a possible anti-doping rule violation” and that Sakho will respond to UEFA on the matter.

The positive test came after the Reds’ 1-1 draw against Manchester United at Old Trafford in the Europa League last month and it is believed that Sakho did not know the composition of the supplement and has told the club he acted in good faith.

The 26-year-old has until Tuesday to respond to the charge and will likely ask for a B sample to be tested.