United Russia has called on Federation Council Speaker Sergei Mironov to resign as tensions between pro-Kremlin parties rise ahead of December's State Duma elections and the 2012 presidential vote.
"We have a position on Mironov: He must renounce his mandate as senator," Boris Gryzlov, speaker of the Duma and chairman of United Russia's supreme council, said in a statement Friday.
Mironov, who stepped down as chairman of the Just Russia party last month but remains the formal leader of the party, which competes with United Russia, said on his blog that he was being subjected to "politically motivated persecution."
He was appointed to his senator's seat by the United Russia-dominated St. Petersburg legislature, which said last week that it was considering recalling him. Mironov, a long-time ally of Prime Minister Vladimir Putin, has come under fire from United Russia after he recently declared that A Just Russia would not back Putin's candidacy for president next year if United Russia named him as its candidate.