Khabarovsk governor Sergei Furgal was detained on Thursday, accused of having ordered the killing of several business people 15 years ago.
Mr Furgal defeated the candidate of Mr Putin’s United Russia party in elections two years ago.
His party, the ultra-nationalist Liberal Democrat Party of Russia, is usually seen as loyal to the Kremlin.
People are shouting “Putin resign!” at a spontaneous protest in Khabarovsk against the arrest of the region’s governor.
Protests in Khabarovsk region, Far East of Russia in support of governor Sergey Furgal who was arrested earlier this week on suspicion of ordering multiple murders. Thousands of people are out on the streets of Khabarovsk, Komsomolsk on Amur, Bikin and Amursk
People in Khabarovsk have come out to protest against the arrest of their governor, who is not from the ruling United Russia party.