Police in Moscow have detained five independent journalists over the past 24 hours, one of whom said he was beaten in custody, the OVD-Info rights group reported Thursday.

Russia has made on-the-ground reporting increasingly dangerous and illegal since it sent troops into Ukraine two years ago, arresting and fining those who defy the Kremlin's narratives.

SOTAvision journalist Antonina Favorskaya was taken for interrogation late Wednesday after serving 10 days' jail for laying flowers at late opposition politician Alexei Navalny's grave.

Her colleagues Alexandra Astakhova and Anastasia Musatova, who came to meet her at the detention centre where she was set to be released, were also detained by police, SOTAVision said.

Then, early Thursday, police arrested reporters Ekaterina Anikievich from SOTAvision and Konstantin Zharov from RusNews, who were detained while filming near Favorskaya's home.

Zharov told RusNews this may have been the reason they were detained, but OVD-Info says the charges against them remain unclear.

"They told us that we were drug addicts, that we were loitering here with an unclear purpose," he said.

"They did not draw up a custody report, although they kicked me, put a foot on my head, twisted my fingers, mocked me when I tried to get up, demanded to show my rucksack as if it might contain explosives," he told the outlet.

Since launching its assault on Ukraine, Russia has banned, blocked or attempted to censor almost all independent media organisations still operating in the country.

Many independent journalists fled in the wake of the offensive, and those that remain face risks. US reporters Evan Gershkovich and Alsu Kurmasheva are currently in jail awaiting trial.