At least 340 people have been detained at events across 30 Russian cities since the death of Alexei Navalny, President Vladimir Putin’s most formidable domestic opponent, according to rights group OVD-Info.

It is the largest wave of arrests at political events in Russia since September 2022, when more than 1,300 were arrested at demonstrations against a “partial mobilisation” of reservists for the military campaign in Ukraine.

Navalny, a 47-year-old former lawyer, fell unconscious and died on Friday after a walk at the “Polar Wolf” Arctic penal colony where he was serving a three-decade sentence, the prison service said.

OVD-Info, which reports on freedom of assembly in Russia, said the largest numbers of arrests on Saturday occurred in St Petersburg and Moscow, where Navalny’s movement had traditionally been strong, with 74 and 49 detained, respectively, as of 5.09pm.

People lay flowers and pay their last respects to Russian opposition figure Alexei Navalny in Moscow on Saturday. Photo: AP

Footage filmed by Reuters on Saturday in St Petersburg showed dozens gathering by a monument to the victims of repression. Protesters laid flowers and candles, while some sang hymns and others hugged each other, shedding tears.

“I felt very sorry for him and for our country,” said an 83-year-old woman attending the vigil who declined to give her name. “I’m scared.”

A reporter at the scene said some 30 people were arrested soon after the singing finished.

OVD-Info also reported individual arrests in smaller cities across Russia, from the border city of Belgorod, where seven were killed in a Ukrainian missile strike on Thursday, to Vorkuta, an Arctic mining outpost once a centre of the Stalin-era gulag labour camps.

Biden says ‘Putin and his thugs’ caused Navalny’s death

Footage filmed by Reuters in Moscow showed law enforcement bundling people to the ground in the snow, close to a spot where mourners had left flowers and messages in support of the dead opposition leader.

“In each police department there may be more detainees than in the published lists,” OVD-Info said.

“We publish only the names of those people about whom we have reliable knowledge and whose names we can publish.”

Reuters could not immediately verify the count. Police declined to comment.