It’s simple; either this was a military action, in which case it was perfidy, which is a warcrime. Or it was a police action, in which case it was summary execution without due process, aka a Death Squad, which is a crime against humanity.

Further more, if this isn’t an occupation, then it is an unspeakably, unforgivably massive crime against humanity that the people living there have not had their citizenship recognized and their rights as such recognized; far worse than Apartheid. You can’t legally just take land and say “yeah, the land is ours, but the people living on it aren’t.”