Ukraine's military said on Thursday its forces had struck a Russian air base in Crimea overnight, confirming an attack that was earlier reported by a Ukrainian intelligence source.

A brief military statement said the Saky air base in western Crimea had been attacked by Ukraine's defence forces, but gave no further details.

The intelligence source told Reuters the attack was carried out by the SBU security service and navy using drones and Neptune cruise missiles. The attack "hit the target and caused serious damage" to equipment at the air base, the source said.

Russia did not immediately comment on the reports. The Russian military said earlier on Thursday that it had destroyed 19 Ukrainian drones over Crimea and the Black Sea, and gave no details on casualties or damage.

Reuters could not independently verify the reports.

Ukraine has ramped up attacks in the Black Sea and Crimea, which was seized and annexed by Russia in 2014, as Ukrainian forces press on with a nearly four-month-old counteroffensive.

The recent attacks highlight Kyiv's growing missile capabilities as Russia continues to bombard Ukraine from afar with long-range missiles and assault drones.

The source said that at least 12 combat aircraft and man-portable air-defense system were located at the base in western Crimea and that the base was used for training drone operators.

Kyiv said a series of attacks on Crimea last week damaged two Russian patrol ships and destroyed a sophisticated air defence system.

On Wednesday Kyiv said Ukrainian forces struck a Russian Black Sea fleet command post near Sevastopol in Crimea. (Reporting by Tom Balmforth; writing by Anna Pruchnicka; editing by Mark Heinrich and Timothy Heritage)