Russian Communist leader Mr Gennady Zyuganov said today his parliamentary party was starting a campaign to secure a vote of no confidence in President Putin's government.
Mr Zyuganov told reporters his party, which controls 84 seats in the 450-seat State Duma lower house, would in the next few days collect the 90 signatures needed to call the vote.
He said his party - that has so far co-operated with President Vladimir Putin - was unhappy with the economic course of the cabinet headed by Prime Minister Mr Mikhail Kasyanov.
Under parliamentary rules the Duma leadership has to put a no-confidence motion on the agenda within a week if it receives a petition from 90 deputies or more.
The Communists have enough allies in the Duma to call the vote but parliamentary analysts say it is unlikely they will get the simple majority of 226 votes the vote would need to pass.