Ukraine's military said on Monday it had struck one of Russia's main factories producing explosives for a wide variety of ammunition for Russia's army as well as an oil terminal in occupied Crimea fueling Moscow's war effort.

Ukraine's forces have stepped up long-range attacks on strategic Russian targets, particularly oil facilities, as diplomatic efforts to end the more than 3-1/2-year-old war have stalled.

In a statement, Ukraine's General Staff said "numerous explosions" were reported after the strike on the Y. M. Sverdlov explosives factory in western Russia, while a fire had broken out following the attack on the oil depot in eastern Crimea's Feodosia.

It added that Ukrainian forces had also struck an ammunition depot in occupied Crimea.