A Russian military plane crashed in Crimea Peninsula in Ukraine, killing three and wounding one, the Russian Defense Ministry said Friday. The plane crashed at 18:40 Moscow time (1440 GMT) at the Kacha airfield 50 km west of the Russian Navy base of Sevastopol, the ministry's spokesman Col. Igor Konashenkov told local media. The Be-12 plane, belonging to Russia's Black Sea Fleet, crashed during landing, Konashenkov said, adding investigators have been working on the scene of the incident. "The crew's captain, the second pilot and a navigator died in the crash. A radio operator was delivered to the Blacks Sea Fleet military hospital with light injuries where he's receiving treatment," Itar-Tass news agency quoted Konashenkov as saying. Russian Defense Ministry has grounded all flights of Be-12 in service pending the probe results, said the spokesman, adding the plane carried no weapons with it during the flight. Be-12, nicknamed "Seagull", is a two-engine flying boat used for anti-submarine operations, firefighting, rescue operations in the sea. The cause of the accident remains unknown.