The World Anti-Doping Agency has partly restored drug-testing duties to the Russian anti-doping agency.
RUSADA was suspended in 2015 when its staff was accused of helping to cover up drug use, but will now have wide-ranging authority over testing.
After intense negotiations and sweeping personnel changes at the Russian agency, WADA said Tuesday it has now allowed RUSADA to "plan and co-ordinate" drug testing under the supervision of British agency UKAD, which has overseen testing in Russia during the national anti-doping body's suspension.
"Resumption of testing represents an important step forward in rebuilding anti-doping in Russia," WADA president Craig Reedie said. "We strongly encourage Russia to continue their efforts in the interest of clean athletes worldwide."
RUSADA will have free rein to choose which athletes to test, even if UKAD disagrees with its choice, and employees will now be allowed to collect samples from athletes. Previously, UKAD oversaw testing and hired private firms to collect the samples.
"UKAD will continue to be involved in the training and development of RUSADA," WADA spokeswoman Maggie Durand told The Associated Press in an email. "UKAD does not have the authority to overrule RUSADA testing plans."
Two WADA appointees attached to RUSADA since last year will monitor the testing, Durand added.
Samples will have to be sent to laboratories abroad. Russia's only drug-testing laboratory remains suspended after its former director said he switched dirty samples for clean ones to cover up doping.
WADA said it allowed RUSADA to resume testing after Russia fulfilled some conditions, including releasing some blood samples from the suspended lab and providing guarantees that drug testers would be allowed in "closed cities" where many Russian athletes train in military units.
Earlier Tuesday, an accountancy executive took the place of pole vault great Yelena Isinbayeva as RUSADA chair. Alexander Ivlev, who heads financial services firm EY's Russia operations, was elected Tuesday to chair the RUSADA supervisory board.
Isinbayeva had first been appointed as chair in December, which angered WADA because of her persistent criticism of probes into Russian doping. Isinbayeva stepped down as chair last month because WADA said her senior role at the Russian Olympic Committee was a conflict of interest.