BEIJING — Two powerlifters have been banned for two years each for failing doping tests, bringing to four the number of athletes caught using illegal substances leading up to the Beijing Paralympics.

Facourou Sissoko of Mali and Liudmyla Osmanova of Ukraine gave positive tests for steroids in out-of-competition tests, the International Paralympic Committee said today.

Two other athletes had already been sent home for failing pre-games doping tests — German wheelchair basketball player Ahmet Coskun and Pakistani powerlifter Naveed Ahmed Butt.

Sissoko tested positive for the anabolic agent Boldenone metabolite in a Sept. 6 urine sample. Osmanova tested positive for another anabolic agent, 19-Norandrosterone, in an Aug. 29 urine sample.

The IPC said Thursday it had carried out 461 tests for the Beijing Paralympics. It will conduct about 1,000 tests before the games end on Sept. 17.

Six athletes tested positive during the recently completed Beijing Olympics. Two hammer throwers from Belarus, who won silver and bronze medals, are still under investigation after testing positive for testosterone.

Dozens of athletes also were kept out of the Olympics after failing or having suspicious pre-games tests.