Russia's ruling party has swept regional elections in several provinces this weekend, easily maintaining its grip on power, according to early returns available Monday.
United Russia won an average of 60 percent of the vote to fill seats in regional legislatures in six provinces _ an increase compared with the last round of regional elections in March when the party got about 50 percent.
United Russia is chaired by Vladimir Putin, who has shifted into the prime minister's seat following his eight-year presidency and remains widely popular. Putin is widely believed to want to seek re-election in 2012 after his protege Dmitry Medvedev's four-year presidential term ends.
United Russia, which has many other top officials and lawmakers among its members, has dominated the federal parliament and holds the majority of seats in most regional legislatures across the country.
Two other pro-Kremlin parties in the lower house of Russian parliament, Just Russia and Vladimir Zhirinovsky's nationalist party, criticized United Russia for what they described as flawed election proceedings in some regions.
Zhirinovsky told reporters that his party's observers witnessed numerous violations.
"There was everything: bribery, blackmail and threats," he told reporters in Moscow, according to the Interfax news agency. "United Russia will always have it all; this is a new modification of the Soviet Communist Party."
Sergei Mironov, the speaker of the Russian parliament's upper house who leads Just Russia, was more cautious, but he argued for a legal ban for government officials to join any party.
Mironov said his party might consider protesting the election's outcome like it did a year ago when Just Russia, Zhirinovsky's party and the Communists walked out of parliament in protest following regional elections they called unfair. They returned to parliament shortly after.
Communist Party chief Gennady Zyuganov said his party would challenge election results in three regions.
United Russia rejected claims of foul play. One of its leaders, Sergei Neverov, proposed amending the Russian legislation to make unfounded claims of electoral violations punishable by law.