Russia's lower house of parliament Friday stripped a leading anti-Vladimir Putin deputy of his mandate, in an unusual move critics said was revenge for his scathing criticism of the Kremlin.

The State Duma voted 291 in favor with 150 against and three abstentions to strip 'A Just Russia' party member Gennady Gudkov of his mandate over alleged conflicting business interests.

Gudkov immediately walked out of the chamber, shaking his fist in defiance and embracing his party colleagues in farewell.

"We have shamed ourselves today in front of the whole world," Gudkov told reporters after the vote, saying he would appeal the decision at the supreme court.

"I am going to continue the struggle and I will not leave the country and hide like a hare. The country has made one step towards civil war."

Gudkov is one of the leading figures in the mass demonstrations against Putin's rule that have rocked Russia since December and he was one of very few figures in the often pliant chamber to vehemently criticize the Kremlin.