KHABAROVSK: Tens of thousands of people took to the streets in Russia's Far East in a rare show of defiance against the Kremlin to protest against the arrest of a popular governor.

The huge rallies in the city of Khabarovsk on the border with China present the Kremlin with a growing headache, observers say, and come after President Vladimir Putin this month oversaw a controversial vote that allows him to extend his hold on power until 2036.

The rallies in Khabarovsk, a city of some 600,000 people, began a week ago following the sudden arrest of popular governor Sergei Furgal in a murder probe.