Russia's electoral chief has said that there have been over 1,000 waves of distributed denial-of-service (DDoS) attacks targeting Russian election infrastructure in recent days.
The attacks appeared to have been carried out by "highly professional, well-coordinated groups using artificial intelligence tools", Ella Pamfilova, chair of Russia's Central Election Commission, said on Sunday.
DDoS attacks involve overwhelming a system with internet traffic so that it is unable to function normally.
"Over the past period, more than 1,000 waves of DDoS attacks have been recorded against infrastructure in Russia that is specifically involved in the electoral process," Pamfilova was quoted as saying by Russian news agencies.
Voting is currently under way in Russia to determine all 450 seats in the lower house, the State Duma.
The ruling United Russia party, which backs President Vladimir Putin and has won every parliamentary election in Russia since 2003, is widely expected to secure another victory.
Putin on Friday accused Ukraine of trying to interfere in the election, citing what he said was a Ukrainian strike on the home of an election official in the Russian-occupied part of Ukraine's Zaporizhzhia region.
Putin told the nation in a televised address before the election that the vote would underline support for Russian troops fighting in Ukraine.
"Your choice, and your will, will once again demonstrate that millions of people stand behind our soldiers, that we are a united people bound together by shared values, historical memory, and love for our homeland, and that no one will succeed in dividing or intimidating us," said Putin.
Initial results are expected to start emerging at around 1800 GMT on Sunday, with more complete results available on Monday.
