Three Iranian officials, including the country's Foreign Minister Hossein Amirabdollahian, were on board a helicopter carrying President Ebrahim Raisi that crashed in heavy fog on Sunday afternoon, killing all four.
Several bodyguards and flight crew members were also killed in the accident.
Here is what you need to know about the three officials:
Hossein Amirabdollahian
Hossein Amirabdollahian, 60, was Iran’s Foreign Minister since 2021.
He earlier served as deputy foreign minister for Arab and African affairs, and the ambassador to Bahrain, among other roles in a long career in diplomacy.
Described as an “anti-western conservative”, Mr Amirabdollahian, from the central city of Damghan, was known for close ties with the Islamic Revolutionary Guard Corps and a staunch backer of Iranian proxy groups across the region.
He was particularly close to the IRGC's Quds Force commander, Gen Qassem Suleimani, who was killed in a US air strike at Baghdad airport in January 2020.
Mr Amirabdollahian once described Suleimani as “the most worthy icon of global peace”.
As Foreign Minister, he led Iran's opposition to curbing its growing nuclear activity, promoted Iranian proxy activity across the region against Israel and the US, and hit out at international sanctions against Tehran.
In April, he warned that Iran was ready to respond at “maximum level” in the event of a further attack from Israel after a strike on Isfahan.
Earlier in June, he met officials from the UN's International Atomic Energy in Iran as the organisation faced increasing difficulty in monitoring nuclear activity in the country.
He also brought Iran closer to other regional powers, most notably rekindling diplomatic ties with Saudi Arabia in March 2023.
Ayatollah Mohammed Ale-Hashem
Born into a clerical family, Ayatollah Mohammed Ale-Hashem was a representative of supreme leader Ayatollah Ali Khamenei in East Azerbaijan province and delivered Friday sermons in the city of Tabriz.
According to a biography on his website, Mr Ale-Hashem, who studied at a seminary in Qom, was also the head of the army's “political ideological organisation”.
Malik Rahmati
Mr Rahmati, 42, was the governor of Iran's East Azerbaijan province and took office last year, having served as deputy economy minister and head of the Privatisation Organisation of Iran.
He was formerly the deputy director of Astan Quds Razavi, which oversees the Imam Reza shrine in Mashhad, and worked in the Interior Ministry.
He was born in Maragheh, East Azerbaijan province, and was Iran's youngest governor, according to Iranian media.
Mr Rahmati travelled with Mr Raisi for the inauguration of a jointly developed dam on the border with Azerbaijan, and was reportedly hoping to secure government support to revive the Aras Corridor project, connecting Azerbaijan with the Azeri exclave of Nakhchivan through Iranian territory.
