TEHRAN -- Iran's Supreme Leader Ali Khamenei on Monday appointed the country's First Vice-President Mohammad Mokhber as interim president following the death of President Ebrahim Raisi in a helicopter crash.

He made the remarks in a message extending condolences over the "martyrdom" of Raisi and his accompanying team's members, including Foreign Minister Hossein Amir-Abdollahian, in a helicopter crash in the northwestern province of East Azarbaijan, according to a statement published on his website.

The leader described Raisi as a "popular, capable, hard-working and indefatigable" president, expressing great sadness at receiving the "bitter news of his martyrdom."

Khamenei said according to Article 131 of Iran's constitution, the first vice-president would be appointed at the helm of the executive branch.

He stressed that the first vice-president was duty-bound to, in cooperation with the parliament speaker and judiciary chief, make the arrangements for the election of the new president within 50 days.

The crash occurred on Sunday in Varzaqan County as Raisi, along with his accompanying team on board three helicopters, was on his way from Khoda Afarin County, where he had attended the inauguration ceremony of a storage dam along with his Azerbaijani counterpart Ilham Aliyev earlier in the day, to the provincial capital Tabriz for the inauguration of a petrochemical complex.

The other members onboard Raisi's helicopter, including East Azerbaijan's Governor Malek Rahmati and the Friday prayers leader Tabriz Mohammad Ali Ale-Hasehem, as well as the flight crew, also lost their lives.