Ivan Golunov, who investigated corruption among Moscow city officials, alleges he has been framed and beaten in custody.

A court in Russia has put a journalist known for investigating corruption among Moscow city officials under house arrest.

Ivan Golunov, who was detained this week for alleged drug offences, was taken to court on Saturday after being hospitalised with suspected head injuries.

Doctors who examined the 36-year-old journalist rejected his lawyers’ claims that he had broken ribs and a concussion, while saying he had scratches on his back and a bruised eye.

Golunov was on his way to a meeting with a source on Thursday when he was detained in central Moscow and illegal drugs were found in his rucksack, according to the police

His employer, online news portal Meduza, said in a statement: “We are convinced that Ivan Golunov is innocent. Moreover, we have grounds to believe that Golunov is being persecuted because of his journalistic activity,” according to Reuters news agency.

Meduza is based in Latvia, an EU member state, to avoid Russian censorship but some of its journalists live in Russia.

A lawyer for Golunov, who is known for investigating alleged corruption among Moscow city officials, said he believed police had planted the drugs on his client to frame him and that he had been physically beaten.

Golunov was charged with attempted dealing in the designer drug mephedrone and cocaine.

Rights groups Amnesty International said there was evidence that the authorities were fabricating drugs charges to shut up their critics.

“Everything indicates that the authorities are planting drugs on their targets to shut them up with a jail sentence,” said Natalia Zvyagina, director of Amnesty International’s branch in Russia.

After his detention on Thursday, Golunov told a representative of Russia’s presidential rights council, which advises Vladimir Putin, that police had punched him and stood on his chest.

His lawyer Pavel Chikov said paramedics suspected he had broken ribs and a concussion.

Golunov’s detention has prompted widespread outrage with supporters holding protests outside police headquarters [Vasily Maximov/AFP]

A paramedic who examined him told Interfax news agency that he had numerous grazes to his chest, injuries to his ribs and a suspected head injury, while police have denied he was beaten.

Outrage over detention

Golunov’s detention has prompted widespread outrage, with supporters holding protests outside the police headquarters and the court.

Meduza posted photographs of people holding placards in support of Golunov in cities around Russia and abroad.

The US embassy in Moscow wrote on Twitter: “We call for the release of Ivan Golunov,” saying he “should not suffer persecution over his professional activities”, while the British Embassy called his case “concerning”.

Around 20 supporters protested outside the Russian embassy in Berlin with slogans such as “Free Golunov”.

“Ivan received threats. Two months ago, they became almost daily,” Meduza General Director Galina Timchenko told journalists outside the court. “They said ‘we’ll bury you forever’,” she added.

While journalists at Russia’s dwindling number of independent media resources frequently face criminal probes, physical attacks and official pressure, drug charges are not common.

Reporters Without Borders warned Golunov’s arrest could mark “a significant escalation in the persecution” of independent journalists in Russia.