June 10, 2010, 4:50 p.m. (ET)

GENEVA(AP) Two Belarusian hammer throwers had their Olympic medals reinstated Thursday after the world sport's highest court determined their doping tests were mishandled by the Beijing laboratory.

The Court of Arbitration for Sport said doping tests of Vadim Devyatovskiy and Ivan Tsikhan were invalid because international laboratory standards were not respected in what it said was an “unusually complex doping case.” CAS said the medals should be returned.

Devyatovskiy and Tsikhan won silver and bronze medals, respectively, at the 2008 Beijing Olympics.

They tested positive for elevated testosterone after the hammer throw final and were disqualified and stripped of the medals by the International Olympic Committee.

The silver medal was subsequently given to Krisztian Pars of Hungary and the bronze to Koji Murofushi of Japan. Primoz Kozmus of Slovenia won the gold medal.

The IOC said it was disappointed by the CAS ruling and “considering all possible options.”

Devyatovskiy and Tsikhan denied doping and appealed to CAS on Dec. 31, 2008, to overturn the IOC ruling.

Although the three-man CAS upheld their appeal Thursday, it said the decision “should not be interpreted as an exoneration of the athletes,” and the court did not say the athletes are free of any doping suspicion.

But CAS ruled that the Beijing National Laboratory, which carried out the tests, had violated “documentation and reporting requirements.”

CAS said the lab had provided no “plausible explanation” for interruption of the automated testing procedure of the IRMS - isotope ratio mass spectrometry - instruments.

CAS also said the lab breached international standards by having the same analyst test both the “A” and “B” samples. Doping samples are divided into two, with the “B” used as the backup to confirm any positive finding in the “A.”

The departure from these international standards “justify the annulment of the tests' results for both athletes,” CAS in a statement.

In a statement, the World Anti-Doping Agency said it was “concerned” with the work done by the lab, and “disappointed” with the CAS decision.

“As in every case where departures from the International Standard for Laboratories are reported, WADA will follow up with the laboratory in order to request a complete report,” the statement said. “WADA will be in a position to comment once it has received and carefully considered this report.”