June 4 - Ukraine launched attacks on the two main centres in the Russia-annexed Crimea peninsula, Kremlin-installed officials in the region said early on Thursday, a day after Moscow and Kyiv traded strikes on each other's cities.

Sergei Aksyonov, the Russia-appointed head of Crimea, writing on Telegram, said Ukrainian forces had hit a non-residential part of Simferopol, the peninsula's main administrative town. The strike killed three people and injured seven, he said.

In the Crimean port of Sevastopol, the local Russia-installed governor, Mikhail Razvozhayev, said air defence units had intercepted more than 20 Ukrainian drones.

Razvozhayev made no mention of casualties, but said drone debris had damaged some buildings. The air raid alert remained in effect in the city for nearly five hours.

Russia seized and annexed Crimea in 2014 - well before its 2022 full-scale invasion of Ukraine - after public protests prompted a Moscow-friendly president to flee Ukraine.

Leaders in the region have taken measures to tackle fuel shortages after an intensifying campaign of Ukrainian strikes on oil industry targets, some deep inside Russia.

On Wednesday, each side struck the other's cities.

In Kramatorsk, one of Ukraine's critical "fortress cities" along the 1,200-km (775-mile) front line, Russian shelling killed at least three civilians, according to Vadym Filashkin, governor of Ukraine's eastern Donetsk region.

In the adjacent Dnipropetrovsk region, local governor Oleksandr Hanzha said Russian forces had injured eight people near the main regional centre of Dnipro.

Ukraine's attacks on Moscow's oil industry included a strike on an oil terminal in St Petersburg on Wednesday. Zelenskiy said the strikes enable Ukraine "to end this war on equal footing".

In Russia's border region of Bryansk, Acting Regional Governor Yegor Kovalchuk said a Ukrainian drone had killed a crane operator working for the local utility.