Apple Inc issued alert messages on Wednesday to at least six activists and researchers who have been critical of Thailand's government, warning it believed their iPhones had been targeted by "state-sponsored attackers", according to activists and the alerts reviewed by Reuters.

Apple and Thailand's Digital Ministry did not immediately respond to a request for comment.

Prajak Kongkirati, a political scientist at Bangkok's Thammasat University, said he had received two emails from Apple warning it believed his iPhone and iCloud accounts...