Prime Minister Najib Mikati of Lebanon has declared a three-day official mourning period for the unprecedented death of Iranian President Ebrahim Raisi and foreign minister Hossein Amirabdollahian, who perished in a helicopter crash on Sunday.

The Hezbollah militant group expressed condolences to the Iranian authorities on the passing of their leader, describing him as a “great brother” and ferocious protector of Islamic principles and the faithful.

“We have known Seyyed Ebrahim Raisi for many years; he was our great brother, a strong supporter, a staunch defender of the issues of the Islamic Ummah, at the forefront of which is the issue of al-Quds and Palestine,” Hezbollah said in its condolence message.

Mr Raisi, 63, according to Hezbollah, was “a supporter and friend of the resistance movements and their standard-bearer in all political and diplomatic forums around the world.”

Messrs Raisi and Amirabdollahian died in the copter crash near the mountains of Jolfa after inaugurating a dam project. 

Supreme Leader Ayatollah Ali Khamenei already said Vice-President Mohammad Mokhber will be the acting president pending the organising of elections for a new president, which must happen within 50 days.