Boris Gryzlov had served as speaker of the State Duma for eight years and helped make it a reliable rubber stamper of Putin's decisions.

Putin has ruled Russia for nearly 12 years as president, then prime minister, and he is now campaigning to reclaim the presidency in March.

However, Putin's authority has been hurt by the Dec. 4 parliamentary election, which saw his United Russia party lose about 20 percent of its Parliament seats and barely retain its majority. Reports of widespread fraud in the voting also led to widespread anti-government protests across Russia last weekend, the largest the nation had seen since its Communist days.

Another large anti-Kremlin protest is scheduled late this month, and that has left authorities scrambling for ways to stem the tide of discontent.