Alexei Navalny, the most outspoken critic of Putin, died in an Arctic prison on February 16.
Police arrested at least 67 people across Russia on Friday at tributes to opposition leader Alexei Navalny on the day of his funeral, according to the rights monitoring group OVD-Info.
OVD-Info said it knew of "at least 67 arrests in 16 towns", including six arrests in Moscow where Navalny's funeral was held, drawing large crowds.
The group had said earlier that 18 people were detained in Novosibirsk.
The Kremlin had warned that action would be taken against "unauthorised" protests and there was a large police presence at the funeral service and burial in Moscow.
Navalny, the most outspoken critic of Russia's President Vladimir Putin, died in an Arctic prison, authorities announced on February 16.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)