In 1941 the British invaded the Mandated territory of Syria. Not a sovereign state, but the British never pretended to be anything other than "occupiers". The same is true when the Japanese invaded New Guinea in 1942, or when the USA invaded the Caroline Islands in 1943-44. None were "sovereign states", but all were placed under a belligerent occupation.
UN to hold off on separate Afghan bombing probe for now (Reuters)
from the article: Netanyahu-appointed panel: Israel isn't an occupying force in West Bank