Yelena Bogolyubova was held by police for several hours on July 16 after she picked up a package from a Moscow post office containing pills for her son, who suffers from an incurable genetic condition.

Lida Moniava, who is deputy director of the Moscow hospital where Bogolyubova’s son is being treated, said Bogolyubova was released after several hours.

It was unclear if she would face criminal charges.

In a post to Facebook, Moniava said doctors have recommended a drug known as Frisium to treat her 10-year-old son's seizures. But the drug has not been approved for use in Russia, and her purchase, and receipt, of the drug was illegal under Russian law.

Moniava said Bogolyubova's 9-year daughter died of the same disease several months ago.

Moniava said the case was not the first involving people who faced criminal charges for buying unregistered drugs online or bringing such medicines from abroad.

The incident, and the broader issue of Russians obtaining unregulated pharmaceuticals online or from outside of the country, has drawn the Kremlin's attention, according to spokesman Dmitry Peskov.

"We will certainly talk with the Health Ministry and ask them to expedite the process” for registering prescription drugs manufactured outside of Russia, Peskov was quoted by the Interfax news agency as saying.

Based on reporting by BBC and Interfax