Apple Inc. last week notified 11 U.S. State Department employees in Uganda that their iPhones were hacked, and investigators have linked the attack to a tool developed by NSO Group, an Israeli technology company that was blacklisted by the Biden administration, according to a person familiar with the matter.

Some of the targeted State Department employees were foreign service officers who are U.S. citizens, while others appear to be locals working for the embassy, the person familiar with the matter said. The hacked phones were linked to State Department email addresses, the person said.