The Russian Communists on May 25 expelled the State Duma speaker, Gennady Seleznyov, for disobeying a party ruling that he resign his post.
The Communist Party last month voted for Seleznyov to quit after the Duma leadership reshuffled committee chairs, leaving the Communists with just two of the nine posts they had held.
The party also asked the two remaining Communist heads of committee to resign.
But Seleznyov, cultural committee chief Nikolai Gubenko and Svetlana Goryacheva, the head of the Duma's committee on women, families and youth, all refused to give up their posts. All three were voted out of the party Saturday at a closed plenum.
Seleznyov said he would not join another party -- and he showed no intention of stepping down from the speaker's post. Putin has supported that decision, media reported.
Like other political parties in Russia, the Communists long refrained from criticizing Putin, and they have supported many of the government's initiatives in the legislature. But they have recently stepped up their opposition, casting themselves as champions of a strong Russia.
Meanwhile, Zyuganov said Saturday that the plenum had adopted a declaration on national security, including the dismissal of the U.S.-Russian arms reduction treaty signed Friday as "a full, unconditional capitulation by Russia," Itar-Tass reported.
He said that the document called for preparations for a vote of no-confidence in the government.