KYIV (AFP) - Ukraine said on Friday (June 10) it had struck Russian military positions in the southern Kherson region, where Kyiv's army is fighting to reclaim territory captured by Moscow's troops early in their invasion.

"Our aircraft carried out a series of strikes on enemy bases, places of accumulation of equipment and personnel, and field depots around five different settlements in the Kherson region," the Defence Ministry said in a statement.

Kherson, just north of the Crimean peninsula that was annexed by Russia in 2014, was among the first regions to come under Russian control following the Feb 24 invasion.

Ukraine has launched an offensive to recapture territory there and the presidency said in a Friday morning briefing that the military situation there remained "tense".

"A series of loud explosions were heard throughout the day, fighting continues on the borders of the region," it said.

Moscow's authorities in occupied Kherson have floated holding a referendum on integrating with Russia, mirroring a controversial vote in Crimea in 2014.

They earlier announced the Russian currency, the rouble, was being introduced into the region.