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

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

Navalny, a 47-year-old former lawyer, fell unconscious and died on Friday after a walk through the “Polar Wolf” Arctic prison 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 number of arrests on Saturday were in St. Petersburg and Moscow, where Navalny’s movement had traditionally been strong, with 74 and 49 detained, respectively.

Images filmed by Reuters on Saturday in St. Petersburg showed dozens of people gathered next to a monument to the victims of the repression. The protesters laid flowers and candles, while some sang hymns and others hugged each other and shed tears.

“I felt very sorry for him and for our country,” said an 83-year-old woman who attended the vigil and did not want to give her name. “I’m scared,” she added. A Reuters journalist at the scene said about 30 people were arrested shortly after the chanting ended.

OVD-Info also reported individual arrests in smaller Russian cities, from the border town of Belgorod, where seven people were killed in a Ukrainian missile attack on Thursday, to Vorkuta, an Arctic mining outpost that was once the center from the gulag labor camps of the Stalin era.

Footage filmed by Reuters in Moscow showed law enforcement bundling people on the ground in the snow, near 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 on the published lists,” states OVD-Info. “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. The police declined to comment.