Three top Russian dailies on Monday published the same front page in an unprecedented act of solidarity over the arrest of an investigative reporter on drugs charges.

"I am/we are Ivan Golunov," the Kommersant, Vedomosti and RBK newspapers declared in giant letters on their front pages.

For the first time in their history, three Russian newspapers will print identical above-the-fold designs on their front pages. They read "I/WE ARE IVAN GOLUNOV." pic.twitter.com/FCuEY2LEIv — Meduza in English (@meduza_en) June 9, 2019

Golunov, a 36-year-old investigative reporter with Meduza, an independent Russian-language media outlet, was detained last week over allegations that he manufactured and dealt drugs.

His arrest sparked outrage among Russian journalists and supporters who say the charges against him are a punishment for his reporting.

Golunov faces between 10 and 20 years in prison if convicted.

EPA

In identical statements published on their front pages, the three newspapers said Golunov's prosecution was an act of intimidation against Russian society and demanded an investigation into the policemen who had detained him.

"We demand that the law be observed by everyone and for everyone," they said.

Golunov was released from pre-trial jail at the weekend and placed under house arrest after hundreds of supporters gathered outside a Moscow courtroom.

The three newspapers said they welcomed the more lenient pre-trial conditions but said they did not consider the evidence presented by investigators to be convincing.

AP

"We do not rule out that Golunov's detention and subsequent arrest are linked to his professional activities," they said.

All three newspapers are privately owned but increasingly have to toe the government line.

During his two decades in power, President Vladimir Putin has silenced most of his critics and muzzled the media. The few opposition and independent media that still operate in Russia are under huge pressure, Kremlin critics say.

Golunov has been charged with attempted dealing of a "large amount" of designer drug mephedrone and cocaine.

His lawyer and supporters pointed to egregious violations in his case.

Police released pictures of a drug laboratory that Golunov allegedly ran but later admitted that only one of the photos was taken in the journalist's apartment.

The Meduza website is based in EU member state Latvia to circumvent censorship from Moscow, but some of its journalists live in Russia.

Golunov's detention has prompted statements of concern from the European Union, the United States, the OSCE and the Council of Europe, among others.

Since Friday, Russians have held one-person pickets in front of Moscow's police headquarters - the only form of protest that does not require prior approval from Russian authorities.

'Carefully monitoring'

The Kremlin said on Monday it was carefully monitoring the case of Golunov and admitted it threw up a "great number of questions."

"We are carefully monitoring how this case is developing," Russian President Vladimir Putin's spokesman Dmitry Peskov said.

"This concrete case has triggered a great number of questions."