Russia-Ukraine war LIVE updates: Russian shelling in Ukraine's Kharkiv region kills 15, governor says

Sergey Aksyonov, head of Russian-annexed Crimea, had on Monday accused Ukraine of firing on a Black Sea oil drilling platform off the peninsula, leaving three people injured and another seven missing.

"On those towers, Russia had organised small garrisons and stored equipment for air defence, radar warfare and reconnaissance," Sergiy Bratchuk of Odessa's regional military administration told an online briefing.

It targeted a rig with four towers some 70kms off the Russian-annexed Crimean peninsula, which Ukraine said was being used as a military installation.

The attack, which took place on Monday, was the first such strike against offshore energy infrastructure in Crimea since Russia invaded Ukraine on February 24.

Ukraine has admitted striking an oil drilling platform in the Black Sea, saying Tuesday it was being used by Russian troops as a military installation. (AFP)

He was accused of discrediting the country's military after speaking out against Russia's military action in Ukraine during the council's session in March.

Moscow's Meshchansky district court ordered Alexei Gorinov to be kept in custody pending his trial. Gorinov, a member of the municipal council of Moscow's Krasnoselsky District, has remained in jail since his arrest in April.

A court in the Russian capital on Tuesday extended the arrest of a municipal legislator charged with discrediting the country's military after his criticism of Russia's military action in Ukraine. (AP)