Russian police have charged an investigative journalist with attempting to deal a "large amount" of illegal drugs, his lawyer said Saturday.

"Ivan Golunov has been charged as a defendant -- attempted dealing," his lawyer Pavel Chikov wrote on Telegram messenger service.

Golunov, a reporter for Meduza independent news website, was detained on Thursday for possession of five packages of mephedrone, a designer drug, Moscow police said, later adding they found cocaine at his flat.

Supporters say the charge is a trumped-up punishment for his reporting on high-level corruption. 

Chikov, a top rights lawyer, posted a police document showing the charge against the journalist involves a "large amount" of cocaine and mephedrone, which means he could face a lengthy jail sentence if found guilty.

Golunov was set to face a court hearing later Saturday where a judge would rule whether to hold him in pre-trial detention, place him under house arrest or set him free.

Journalists were waiting to enter the court building on Saturday afternoon.