A car belonging to Russian presidential hopeful Ksenia Sobchak's campaign chief in the northwestern city of Pskov has been torched in an alleged arson attack.

Viktor Shirobokov's car was set on fire overnight, a statement on Sobchak's campaign website on January 28 said.

Shirobokov used his car to travel to Moscow with signatures of local supporters of Sobchak as part of the procedure necessary to officially register her as a candidate in the March 18 election.

The campaigners said the fire was a planned arson attack and asked local police to investigate.

Hours before the car fire in Pskov, Sobchak was in the capital of Russia's North Caucasus region of Chechnya, where she held a protest at a memorial to slain journalists and held a sign reading, "Freedom for Oyub Titiyev!"

Titiyev, the head of human rights group Memorial's office in Chechnya, is in pretrial detention on a marijuana possession charge he and supporters contend was fabricated.

After Titiyev’s arrest, Memorial's office in Ingushetia and one of its cars in Daghestan were torched in what the group believes were attacks linked to its efforts to challenge Titiyev's arrest.