By Andrew Osborn and Vladimir Soldatkin
MOSCOW, Sept 20 (Reuters) - Ukraine launched what Moscow's mayor called the biggest drone attack yet on the Russian capital on Sunday, as Russians voted on the final day of a parliamentary election that President Vladimir Putin has cast as a test of support for the war in Ukraine.
Voting systems have also withstood waves of cyber attacks, according to election authorities, who said everything was running smoothly despite what they described as external efforts
to derail the State Duma vote - the first since Russia launched its full-scale war in Ukraine in February 2022.
The drone strikes killed three people in the Moscow region and two more in the Russian-held part of Ukraine's Kherson region, including an election official, according to the region's governor and the election commission.
A facility at Moscow's oil refinery, which has been targeted before, was also damaged. As voting got underway in the capital, flames and huge columns of smoke rose from the site on its outskirts.
"The biggest attack by enemy drones has been repelled," Moscow Mayor Sergei Sobyanin said on Telegram. "This unprecedented attack was clearly planned with the aim of disrupting the elections. The enemy did not succeed."
The vote is expected to see the ruling United Russia party easily retain its dominance in a political system critics say does not tolerate dissent.
The Kremlin is likely to present the outcome as evidence of public backing for Putin's policies and for the war, now in its fifth year with no sign of ending soon.
Central Election Commission Chairwoman Ella Pamfilova said the latest attacks had not deterred voters. "The more pressure they put on us, the more we are seeing an unprecedented level of what I would call public unity," RIA news agency quoted her as saying.
Most anti-war candidates have been barred from the ballot. Those who did run from the liberal Yabloko party, which has polled in the single digits in recent years but hoped to tap into war fatigue, said they feared for their freedom after courts handed long jail terms to two senior party figures before the vote for comments about the conflict.
Discrediting the army or spreading what authorities regard as fake news is punishable by lengthy prison sentences.
In a small act of defiance, Yabloko's leader, Nikolai Rybakov, demonstrably spoiled his ballot paper, writing his party's name and the slogan "For peace".
The Kremlin says national unity and some censorship are necessary during what it calls its special military operation in Ukraine. It casts the conflict - Europe's deadliest since World War Two - as part of an existential struggle with a hostile West. Moscow says Ukrainian intelligence services and other enemies are stepping up efforts to stir unrest inside Russia.
PERMITTED OPPOSITION PARTIES COULD BENEFIT
Kyiv, which has suspended elections under martial law, has dismissed the Russian vote as a "pseudo election".
Putin on Friday accused Ukraine of trying to interfere in the vote, citing what he said was a Ukrainian strike that killed an election official in her home in the Russian-controlled part of Ukraine's Zaporizhzhia region on Tuesday. Reuters could not independently verify details of the attack and there was no comment from Kyiv.
Despite what experts see as the election's predictable outcome, the NEST think-tank in Berlin, co-founded by Kremlin critic Mikhail Khodorkovsky, whom Russian authorities have designated "a foreign agent", said the vote could still produce awkward moments for the Kremlin at a time of economic strain.
"The consequences of the war are increasingly being felt within the country, and accumulated anxiety and frustration may translate into votes for the systemic opposition parties that the Kremlin has allowed to remain on the ballot," it said in a note.
It said the Communist party and the New People party could attract votes the authorities would prefer to go to United Russia. Both parties have consistently voted in line with United Russia on major issues.
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.
(Reporting by ReutersWriting by Andrew OsbornEditing by Kirsten Donovan, Ros Russell)
