MOSCOW — Ukrainian authorities say a Russian activist has requested political asylum in their country.

Ukraine’s State Border Guard Service said in a statement on Sunday that a Russian citizen requested political asylum at a border crossing in western Ukraine, citing his activism in Russia. The agency described the man as a political activist who had protested against Kremlin policies.

Ukraine’s Hromadske television late Sunday identified the man as Roman Roslovtsev who is better known for his walks across Red Square in a President Vladimir Putin mask. He has been detained more than 20 times and served 20 days in police custody in May for one of his protest walks.

Since Russia’s annexation of Crimea in 2014 a number of Russian activists have moved to Ukraine to protest Putin’s policies.