In a message to Iranian Supreme Leader Ayatollah Ali Khamenei, Russian President Vladimir Putin said, "Raisi was a 'true friend' to Russia and was admired both at home and abroad.

"Raisi was rightly highly respected by his compatriots and enjoyed great prestige abroad," Putin said in the condolence message released by the Kremlin.

"As a true friend of Russia, he made an invaluable personal contribution to the development of good neighbourly relations between our countries and made great efforts to raise them to the level of strategic partnership," he added.

In his message, Putin said that he would always fondly remember the "remarkable" Raisi.

Chinese President Xi Jinping also expressed his "deep sorrow" over the death of Raisi.

Xi offered his "sincere condolences" to the Iranian government and people, a spokesman for the Foreign Ministry in Beijing said on behalf of the Chinese leader.

Raisi had made "important contributions to maintaining Iran's security and stability, promoting national development and prosperity, and making positive efforts to consolidate and expand the comprehensive strategic partnership between China and Iran."

"His unfortunate death is a great loss to the Iranian people, and the Chinese people have also lost a good friend," the spokesman added.

Expressing her condolence, Italy's Prime Minister Giorgia Meloni said, "I would like to express my solidarity and Italy's solidarity with the Iranian government and the Iranian people."

"I see in these hours that the Iranian authorities recognise the hypothesis of the accident instead of conspiracy theories," she told private broadcaster Canale 5.

European Council President Charles Michel expressed condolences on behalf of the European Union, saying, "Our thoughts go to the families."

Sri Lankan President Ranil Wickremesinghe said he was deeply shocked and saddened by the tragic death of his Iranian counterpart Ebrahim Raisi, Foreign Minister Hossein Amir-Abdollahian and other senior Irani officials in a helicopter crash.

Pakistani Prime Minister Shehbaz Sharif took to X and wrote, "Pakistan had the pleasure of hosting President Raisi and Foreign Minister Hossein Amir Abdollahian on a historic visit less than a month ago. They were good friends of Pakistan. Pakistan will observe a day of mourning, and the flag will fly at half mast as a mark of respect for President Raisi and his companions and in solidarity with Brotherly Iran."

Numerous Arab countries also expressed their condolences.

Qatari Emir Tamim bin Hamad al-Thani took to X and offered his "sincere condolences to the government and people of the Islamic Republic of Iran."

Egypt and Jordan expressed solidarity with Iranians.

Jordan's King Abdullah II said his "deepest condolences go out to the brothers, leadership, government and people of the Islamic Republic of Iran on the death of brother President Ebrahim Raisi."

Syrian leader Bashar al-Assad, a close ally of Iran, expressed his condolences for "this painful incident and the resulting great loss."

The government in Baghdad also expressed its sympathy.

Lebanon, for its part, announced a three-day mourning period.

Raisi and eight other passengers, including Foreign Minister Hossein Amir-Abdollahian, died when their helicopter went down on Sunday over mountainous terrain in dense fog.