Russia annexed the Black Sea peninsula in March after Crimea residents voted overwhelmingly to seek to join Russia.
The referendum was called two weeks earlier, coinciding with the military occupation of the region by armed men in unmarked uniforms.
Shoigu today described claims that the Russian army has mistreated Ukrainian servicemen as "improper and provocative."
Several senior Ukrainian officers including a military base commander were briefly detained by the Russian forces and kept in custody for several days.
In what seems to be a cautious acknowledgement of the Russian military involvement in the peninsula, Shoigu said that Crimea faced "a threat to civilian lives and the threat of a seizure of the Russian military infrastructure by extremist organisations," so Russia "took decisive actions" and "beefed up security of Russian military infrastructure in Crimea."
He stopped short, however, of giving details but said the military "managed to prevent bloodshed." Shoigu said Russia's actions did not violate any international laws because Russia never exceeded the agreed amount of troops stationed on the peninsula.
