Seven people have been killed and 11 others injured after a drone hit a passenger bus travelling through a Russia-controlled part of Ukraine, an official said.

Denis Pushilin, the Kremlin-installed leader of Ukraine's eastern Donetsk region, said the bus was struck in the early hours of Wednesday as it was travelling between Moscow and Simferopol, in Russian-occupied Crimea.

Russia downed more than 350 drones overnight, according to Russian officials.

It comes a day after a massive Russian assault on cities across Ukraine killed at least 22 people, including several women and children.

"In Yenakiyevo, a UAV attacked a Moscow-Simferopol coach; according to preliminary reports, seven civilians were killed," Pushilin said in a Telegram post on Wednesday.

He added that the 11 injured people were receiving medical care.

Drones were downed over Belgorod, Kursk and other western regions, as well as near Moscow and over the Sea of Azov, officials added.

At least 50 drones were downed over the Leningrad region northwest of Moscow, according to the regional governor Alexander Drozdenko.

The region includes the city of St Petersburg, which from Wednesday will host the annual International Economic Forum, an event designed to showcase Russia to the world.

These overnight strikes saw Pulkovo airport temporarily restrict flights, according to Russian aviation watchdog Rosaviatsia.

Meanwhile, an 86-year-old woman was killed following a drone attack in Ukraine's southern Kherson region overnight, Yaroslav Shanko, head of the city's military administration said.

This came as part of a wider attack by Moscow overnight, with Ukraine's air force saying Russia launched 198 drones at several different regions, 189 of which were shot down.

The latest wave of strikes comes a day after Russia launched one of its largest attacks on Ukraine since its full-scale invasion began in 2022.

At least 22 people were killed after Russia launched more than 700 missiles and drones overnight into Tuesday, Ukrainian officials said.

President Volodymyr Zelensky said civilian infrastructure and energy facilities had been targeted across the country, with more than 100 people injured.

Russia's defence ministry said the strikes had been a response to previous Ukrainian attacks, saying in a statement that the "strike objectives" had all been achieved.

The Kremlin said on Tuesday it was carrying out the "systematic strikes" it had pledged after accusing Kyiv of a deadly attack on a student dormitory in an occupied part of eastern Ukraine in late May.

Kyiv said it had hit a Russian military unit.

"This practice will continue," Kremlin spokesman Dmitry Peskov told reporters on Tuesday, claiming the strikes were targeting Ukrainian military infrastructure.