MOSCOW — The chairman of Russia’s governing party, United Russia, resigned from his post as speaker of the lower house of Parliament on Wednesday in an apparent effort to quell some of the uproar over perceived fraud in parliamentary elections last week.

The chairman, Boris V. Gryzlov, is the highest-ranking official in United Russia after Prime Minister Vladimir V. Putin, who serves as the party’s leader. Intensely loyal to Mr. Putin, Mr. Gryzlov played a crucial role during his eight years as speaker in pacifying the Parliament, which he once famously said “was no place for political battles.”

Mr. Gryzlov’s decision underscores the pressure on United Russia, which lost its constitutional majority in the elections, officially receiving 50 percent of the vote, a significant decline in the party’s support. But even that result has been called into question amid widespread accusations that United Russia engaged in ballot stuffing and other fraud.

In a statement on United Russia’s Web site, Mr. Gryzlov gave no specifics about the reason for his departure. He said he would remain United Russia’s chairman, but he would not take a seat in Parliament.