A Russian anti-corruption journalist has been detained on drug-dealing charges in a case that has sparked protests from his supporters.

Ivan Golunov, who has been released on house arrest until 7 August, appeared at a Moscow court on Saturday.

Police are alleging four grams of a synthetic stimulant were found in Golunov's backpack, but many journalists believe the arrest was retribution for the suspect's investigative reporting.

His supporters gathered outside the Moscow courthouse and dozens of people demonstrated in St Petersburg against the arrest.

Boris Vishnevsky, deputy head of the St Petersburg legislative assembly, said at the demonstration: "I don't want people to be persecuted for their political views.


"Tomorrow, they may plant drugs on me, on you, on anybody if we keep silent."

Image: Golunov has been detained on drug charges

Golunov's recent work includes a report on unscrupulous money-lenders who evict debtors from their homes.

The journalist, who works for the independent news website Meduza, has also reported on an organisation allegedly trying to take over Russia's funeral industry.

Meduza editor Ivan Kolpakov told the Interfax news agency Golunov had received threats related to the latter.

A spokesperson from the publication also said the reporter was beaten after his arrest on Thursday.

Golunov appeared in court on Saturday following a medical examination after he complained of feeling ill in police custody.

Image: Police detained a demonstrator showing support for Golunov in Moscow

Moscow's police department said an emergency medical squad was called for Golunov on Saturday afternoon and determined he should be taken to hospital.

It did not specify his medical problem.

Pavel Chikov, head of human rights organisation Agora, told Russian news agencies Golunov was suspected of having concussion and a broken rib.

Golunov broke down in tears on Saturday as he spoke to reporters from a cage in which defendants are held in Russian courtrooms.

The reporter denies being involved with drugs and said he would be willing to help investigators.