The preliminary results announced in Moscow early on September 19 by Central Election Commission (CEC) show United Russia with more than 54.28 percent of the party-list vote, Radio Liberty reports.
Candidates from United Russia, which is backed by Russian President Vladimir Putin, also were leading in most of the 225 single-member constituencies.
Unlike the last two parliamentary elections, only half of the seats will be selected by national party list, with the other 225 being contested in races held in specific districts.
CEC Chairperson Ella Pamfilova said United Russia is on track to win 140 State Duma seats by party ticket and another 203 in single-member constituencies.
Only three other parties were on track to surpass the 5 percent threshold needed in the September 18 election to secure party representation in the legislature. All are loyal to the Kremlin and its policies.
They include the Communist Party with 13.45 percent, the ultranationalist Liberal Democratic Party of Russia with 13.24 percent, and A Just Russia with 6.17 percent.
But the September 18 vote faced the danger of being tarnished by lower voter turnout and a growing number of reported violations.
The CEC said turnout was 47.81 percent of eligible voters — down from about 60 percent in the 2011 State Duma election.
Authorities were closely watching for signs of discontent or unrest, as the country struggles with an economy hobbled by low oil prices, Western sanctions, rising inflation, and falling foreign investment.
Putin hailed the results, telling lawmakers at United Russia’s election headquarters that they were a vote of confidence.
He also alluded the country’s continuing economic problems but insisted that Russians acknowledge lawmakers “are really working hard even though it does not always work.”
“The situation is not easy, people feel that, and they want and hope that the political situation should be stable,” he said.
Voting was also held on the Ukrainian peninsula of Crimea, the first time since Moscow’s annexation of the Black Sea region in 2014.