(Reuters) -Ukraine launched 35 drones at targets across Russia that sparked a brief fire at an oil refinery, took aim at Moscow and disrupted electricity supplies in border areas, Russia said on Sunday, the last day of its presidential election.
Moscow has accused Kyiv of election sabotage with days of strikes on Russian infrastructure, one of the most sweeping air operations on Russian territory since President Vladimir Putin ordered the invasion of neighbouring Ukraine two years ago.
Putin, all but certain to win re-election, has vowed to punish Ukraine for the attacks.
Ukraine's President Volodymyr Zelenskiy thanked his military forces and intelligence for new "long-range capabilities" in his nightly video address on Saturday, without mentioning the reported intensified attacks by his nation's forces.
The Russian defence ministry wrote on the Telegram messaging app on Sunday that 17 drones were destroyed over the southern Russian region of Krasnodar, four over the Moscow region and the rest over six other regions.
"The drones were neutralised, but a fire broke out as a result of the fall of one of the devices," the operational headquarters of the Krasnodar region in southern Russia said on Telegram.
The fire at the Slavyansk refinery in Krasnodar was extinguished and there were no casualties as a result of the fire, although preliminary information indicated one person had died of a heart attack, the administration said.
Roman Siniagovskyi, head of the Slavyansk administrative district, said on Telegram refinery workers had been evacuated and there was no threat to nearby populated areas from the incident.
Reuters could not independently verify the reports.
Ukraine's Ukrainska Pravda newspaper cited a Ukrainian intelligence source as saying Kyiv considered the drone raid a success because a large fire broke out near the crude distillation units which were the primary target.
The Slavyansk refinery, some 70 km (45 miles) north of Krasnodar, processes around 4.5 million metric tons of crude a year, producing fuel mainly for exports, but also sells some gasoline on the domestic market.
A Ukrainian intelligence source told Reuters on Sunday that long-range Ukrainian attack drones launched by the SBU domestic security service had hit 12 Russian oil refineries during the war so far.
Moscow Mayor Sergei Sobyanin said there were no casualties or damage reported from the drones shot down over three districts near Moscow.
North of Moscow four drones were destroyed over the Yaroslavl region, with no damage or injuries reported, Governor Mikhail Yevrayev said on Telegram.
In the border region of Belgorod, an attack by four Ukraine-launched drones damaged electricity and gas lines in one village, said Governor Vyacheslav Gladkov.
Russia's defence ministry said Russian forces also shot down 12 rockets launched from Ukraine towards the Belgorod region on Sunday.
As Russia was facing attacks from Ukraine, Kyiv's military said on Sunday that Russian air attacks had damaged agricultural enterprises and destroyed several industrial buildings in the Black Sea port of Odesa overnight.