Ukraine launched a massive wave of drone strikes against Russia on Saturday night that forced the Crimean bridge to close and grounded flights from Moscow.

Car traffic was suspended over the bridge connecting Crimea with mainland Russia for half an hour this morning, Russian authorities announced, without explaining why.

Moscow’s Domodedovo, Vnukovo and Zhukovsky airports were forced to impose flight restrictions for almost three hours after four Ukrainian drones were shot down near the Russian capital, Russia’s state aviation watchdog reported.

Sergei Sobyanin, Moscow’s mayor, said a fifth drone, close to Domodedovo airport, was later downed, with no casualties or damage reported. However, footage and images circulating on social media appeared to show a hole in the roof of a building at the airport following a drone strike.

Elsewhere, a fireball erupted at an oil refinery in Slavyansk-on-Kuban in Krasnodar Krai, south western Russia, after Ukraine’s sixth drone strike on a Russian oil facility in a week.

The Russian defence ministry said it downed all 17 drones attacking Krasnodar, “but a fire broke out as a result of the fall of one of the devices”, local Russian military intelligence said on Telegram.

The blaze at the refinery was extinguished a few hours later, and preliminary information indicated a worker had died of a heart attack, officials said.

Ukrainian military intelligence was behind the strike, a security service source told Ukrainska Pravda.

Another two drones were shot over the Kaluga region, just south of the Russian capital, and the Yaroslavl region, northeast of Moscow, according to the defence ministry. The latter, around 500 miles from the Ukrainian border, were some of the farthest launched by Ukraine so far.

More Ukrainian drones were downed over the Belgorod, Kursk and Rostov regions that border Ukraine. Vyacheslav Gladkov, the governor of Belgorod, reporting damage to electricity and gas supplies in the area.

In the front-line region of Zaporizhzhia, a fire broke out at a polling station after it was hit by a Ukrainian drone, Tass, the Russian state-owned agency, reported.

Volodymyr Zelensky, Ukraine’s president, did not address the reported attacks in his nightly video address on Saturday, but he thanked his military forces and intelligence “for the new Ukrainian long-range capabilities”, adding “the Russian war machine has vulnerabilities that we can reach with our weapons”.

The wave of strikes came on the final day of Russia’s sham presidential election, with Vladimir Putin poised to extend his near-quarter-century rule for six more years.