Ukraine has for months launched retaliatory drone strikes against Russian energy sites, calling them a fair response to Moscow's own barrages on its cities and power grid.

Russia's nuclear power agency Rosatom said one had targeted the Smolensk nuclear power plant, around 300 kilometres (186 miles) west of Moscow.

Air defences "neutralised a Ukrainian combat drone near the third power unit of the Smolensk nuclear power plant," at around 4:00 am (0100 GMT), it said in a statement.

The debris shattered some windows but caused no major destruction or injuries. The plant remains in operation and there has been no change in radiation levels, Rosatom added.

Ukraine and Russia have throughout the conflict accused each other of targeting nuclear sites, drawing warnings and concern from the International Atomic Energy Agency.

Russia's army captured the defunct Chernobyl nuclear plant on the first day of its military campaign in February 2022, withdrawing a month later.

Moscow also captured -- and still holds -- the Zaporizhzhia nuclear power plant in southern Ukraine, the largest nuclear facility in Europe.

Russia's defence ministry had earlier said it had downed 221 Ukrainian drones overnight.

Ukraine's air force said Russia had fired 40 drones in its own overnight attack -- much fewer than normal.

The governor of Russia's Leningrad region Aleksandr Drozdenko said a fire had broken out on a vessel in the Port of Primorsk, a major facility on the Baltic Sea, but the blaze had been brought under control and there was no risk of an oil spill.

The attacks came after Poland, which borders Ukraine, accused Russia of launching a drone raid on its territory earlier this week.

Moscow has denied targeting the country and said there was no evidence the drones were Russian.