Police officer detains a supporter of Russian investigative journalist Ivan Golunov during a march in Moscow, Russia, Wednesday, June 12, 2019.
Police officer detains a supporter of Russian investigative journalist Ivan Golunov during a march in Moscow, Russia, Wednesday, June 12, 2019.

Russian police have detained opposition leader Alexei Navalny and hundreds of other people who attended a Moscow protest to call for retribution against police who allegedly framed a high-profile journalist, a monitoring group said.

The OVD-Info group, which monitors political arrests, said police Wednesday detained at least 400 people, some of them by force. The group said police began releasing some of the detainees while drawing up charges against others.  

The unauthorized rally follows a surprise police decision to drop charges against journalist Ivan Golunov, who was charged last week with drug dealing after police claimed to have found drugs in his apartment. Golunov, who earned a reputation for exposing corrupt Moscow city officials, denied the allegations.

Authorities said the case was dropped on Monday due to lack of evidence and wrongdoing by Golunov.

The charges were dropped after angry outbursts from his supporters, including three of Russia's most respected newspapers.

Many of the protesters demanded the reform of Russia's law enforcement agencies and the release of detained victims of police.

Authorities had hoped Golunov's release and a promise to punish those involved in framing him would appease his supporters, but they decided to proceed with the protest on Russia Day, a public holiday.

Police officers detain a protester during a march in Moscow, Russia, June 12, 2019.

The Interior Ministry said some 1,200 people participated in the demonstration. Many chanted "Russia will be free" and "Russia without Putin." Others wore T-shirts saying, "I am/We are Ivan Golunov," which mirrored the headlines on the front pages Monday of Russia's three daily newspapers.

Amnesty International's Denis Krivosheev said in a statement the "arbitrary and often brutal arrests of over 400 peaceful protestors, including children, are a perfect example of the cruel repression that brought the protestors to the streets in the first place." He added, "It is outrageous that those who called for his freedom and now for accountability are being punished for their solidarity."

Krivosheev also called on authorities "to immediately and unconditionally release the protestors arrested today."

Authorities warned protest organizers the demonstration would be illegal and would create safety concerns. Russian law requires protests to be approved by authorities in advance.