In a statement on Thursday, Russian authorities said 31-year-old Ms Griner was detained by Moscow police in February based on “objective facts and evidence”.
“She was caught red-handed while trying to smuggle hash oil,” the statement, issued by Rusia’s foreign ministry to CNN, said. “In Russia, this is a crime.”
The remarks were an apparent pushback against a US State Department statement earlier this month which described the basketball player’s arrest as “illegal” and wrongful.
Ms Griner was allegedly detained while attempting to leave Russia with a bag of vape cartridges containing a derisive of cannabis oil.
While the cartridges are legal in most parts of the world, they are banned in Russia under “part 2 of Article 229.1 of the Criminal Code of the Russian Federation (drug smuggling)”, the statement added.
She faces up to 10 years in prison in Russia, and appeared in court on Friday for a hearing on whether or not her detention will be extended. The outcome of that hearing remains unclear.
Russian authorities went on to describe the charges against Ms Griner, who plays for the Phoenix Mercury and a Russian basketball team in the off-season, as “serious, based on objective facts and evidence that is available”.
“The final point in this case should be made by the court,” the statement added.
US officials had not described Ms Griner’s arrest as wrongful until this month. That followed the negotiated release of former US Marine Trevor Reed, who was also detained in Russia.
Additional reporting by The Associated Press.