Vladimir Putin accused Ukraine on Friday of aiming to disrupt Russia's presidential election by shelling Russian territory and using 2,500 armed soldiers to try to pierce his country's borders, and vowed to punish Kyiv for its actions.
The first day of the election was also marred by disruptions including dye being poured into ballot boxes, a Molotov cocktail thrown at a polling station in Putin's home town, and reported cyber-attacks.
Millions of Russians cast their ballots across the country's 11 time zones at the start of the three-day election, which is almost certain to hand Putin six more years in the Kremlin.
The shadow of the Ukraine war fell across the election, with what Putin said was repeated shelling of Russia's western regions and an attempt by Ukrainian proxies to cross into Russian territory in two Russian regions.
"These enemy strikes will not remain unpunished," a visibly angry Putin said at a meeting of Russia's Security Council, which includes military and spy chiefs as well as the most powerful civilian state officials.
Putin said there had been four attacks on the Belgorod region and one on the Kursk region by armed Ukrainian proxies numbering about 2,500. He said they had 35 tanks and 40 armored vehicles and that 60% of the soldiers were killed.
Ukrainian officials said earlier on Friday that Russian armed groups based in Ukraine who are opposed to the Kremlin carried out the attacks in the Belgorod and Kursk regions.
Amid the Ukraine war, the deadliest conflict in Europe since World War Two, Putin, 71, dominates Russia's political landscape and none of the other three candidates on the ballot paper presents any credible challenge.
More than 114 million Russians are eligible to vote, including in what Moscow calls its "new territories" - four regions of Ukraine that its forces only partly control, but which it has claimed as part of Russia. Ukraine says the staging of elections there is illegal and void.
Dye, cyber-attacks
Dye was poured into ballot boxes in Moscow, Russian-annexed Crimea, and the Caucasus region of Karachayevo-Cherkessia, according to Russian media, in apparent anti-Kremlin protests.
CCTV footage of one dye-pouring incident showed a young woman depositing her voting slip before calmly pouring a green liquid into the ballot box. A policeman was seen detaining her immediately afterwards.
A Molotov cocktail was thrown at a polling station in St Petersburg, and a 21-year-old woman arrested, the Fontanka news site reported. Arson attempts were recorded at polling stations in Moscow and Siberia.
Russia's electoral commission chief, Ella Pamfilova, said perpetrators of such acts faced up to five years in prison, and suggested they had been paid for by those seeking to disrupt the vote.
"Listen carefully everyone," Pamfilova said, before setting out the article in the Criminal Code which dealt with disrupting the work of electoral commissions.
As of 18:40 Moscow time (1540 GMT), country-wide turnout was high, at around 26.6%. Demand for electronic voting was so high the system was overloaded.
The Kremlin says Putin, in power as president or prime minister since the last day of 1999, will win as he commands broad support for rescuing Russia from post-Soviet chaos and standing up to what it says is an arrogant, hostile West.
The electoral commission said there had been over 10,000 attacks on electronic voting systems but that they had endured.
