Iran’s President Ebrahim Raisi, Foreign Minister Hossein Amir-Abdollahian, and other officials were confirmed dead on Monday after their helicopter crashed in a mountainous region in the northwest of the country, Iranian state media reported.

Raisi, known as the “Butcher of Tehran” for his role in the mass executions of political prisoners in 1988, left a leadership vacuum, prompting Supreme Leader Ayatollah Ali Khamenei to appoint First Vice President Mohammad Mokhber as interim head of the country’s executive branch.

An Israeli official denied involvement in the crash, stating bluntly to Reuters, “It wasn’t us.” Iran has long supported Hamas, which is currently engaged in a prolonged conflict with Israel.

Iranian State TV reported there was “no sign of life” at the crash site, where the helicopter carrying 63-year-old Raisi, 60-year-old Abdollahian, and other officials made a “hard landing” on Sunday. The crash occurred across a steep valley, with no immediate cause provided. Rescuers spotted the helicopter from approximately 1.25 miles away early Monday, according to the head of the Iranian Red Crescent Society, Pir Hossein Kolivand. The officials had been missing for over 12 hours when the helicopter was first observed.

Raisi and Amir-Abdollahian were traveling in Iran’s East Azerbaijan province when the helicopter made what state TV described as a “hard landing” near Jolfa, a city on the border with Azerbaijan, about 375 miles northwest of Tehran. Later reports indicated the crash occurred further east near the village of Uzi, though details remained conflicting. The governor of East Azerbaijan province, other officials, and bodyguards were also on board, according to the state-run IRNA news agency. Descriptions of the event varied, with some officials calling it a “crash” and others a “hard landing” or an “incident.”

Interior Minister Ahmad Vahidi stated on state TV that the helicopter was forced to make a hard landing due to bad weather and fog. Following the crash, Supreme Leader Khamenei confirmed First Vice President Mohammad Mokhber as the interim head of the executive branch. This incident follows Iran’s recent unprecedented drone-and-missile attack against Israel and ongoing mass protests against its Shiite theocracy in response to economic struggles and assaults on women’s rights.