Vladimir Dyatchin tests positive

MOSCOW -- The Russian Anti-Doping Agency has suspended two-time world open water champion Vladimir Dyatchin of Russia for failing a doping test.

RUSADA says in a statement late Thursday that tests detected an unspecified "banned substance" in the A sample given by Dyatchin at last month's Russian championships.

Dyatchin won the 10-kilometer open water event at the 2003 and 2007 world championships. On the latter occasion, he was stung by a jellyfish during the race. He finished seventh in the 10km at the 2012 Olympics.

Dyatchin's positive test increases the pressure on Russia, which will host next year's world aquatics championships in Kazan.

Double world champion swimmer Yuliya Efimova was banned for 16 months in May after testing positive for a steroid. Two other Russian swimmers remain suspended after positive tests at international competitions.