LONDON (AP) — British 4x100-meter relay silver medalist Chijindu Ujah has been provisionally suspended by the Athletics Integrity Unit for an alleged doping violation at the Tokyo Olympics.

The AIU announced Thursday that the doping control laboratory in Tokyo had notified the International Testing Agency of an “adverse analytical finding” in Ujah’s doping sample.

It said Ujah’s sample contained the prohibited substances ostarine and S-23, which are selective androgen receptor modulators (SARM) and help with building muscle.

Ujah was part of the British quartet alongside Zharnel Hughes, Richard Kilty and Nethaneel Mitchell-Blake who finished second to Italy in a close race.

If found guilty, Ujah and the British team could be stripped of the silver medal.

The AIU also confirmed that 1,500-meter runner Sadik Mikhou of Bahrain, Georgian shot-putter Benik Abramyan and Kenyan sprinter Mark Otieno Odhiambo have also been provisionally suspended following earlier adverse tests during the Tokyo Games.