ISTANBUL 

Oman, Iraq and Azerbaijan congratulated Mojtaba Khamenei on Monday on his selection as Iran’s new supreme leader.

He was declared the successor to his father, Ayatollah Ali Khamenei, who was killed in a US-Israeli airstrike on Feb. 28.

Oman’s Sultan Haitham bin Tariq Al Said sent a cable of congratulations to Mojtaba, expressing his best wishes to the new leader in assuming his responsibilities, according to the state news agency ONA.

The Omani ruler became the first Arab leader to congratulate him on his new post.

Iraqi Prime Minister Mohammed Shia al-Sudani issued a statement expressing confidence in Iran’s new leadership “to manage this sensitive stage and strengthen the unity of the Iranian people in facing current challenges.”

Al-Sudani also reaffirmed Iraq’s solidarity with Iran and support for “all steps aimed at ending the conflict (with Israel and the US) and rejecting military operations against its sovereignty,” stressing the importance of preserving regional stability and the security of its peoples.

Azerbaijani President Ilham Aliyev also congratulated Khamenei and extended condolences over the death of his father.

“Once again, I express my condolences to you in connection with the tragic death of your father, the Supreme Head of the Islamic Republic of Iran, Ayatollah Ali Khamenei,” Aliyev said in a statement published on the presidential website.

He also expressed hope for developing relations between the two countries “in the field of mutual respect and trust in the interests of our peoples.”

Chinese Foreign Ministry spokesman Guo Jiakun said his country opposes “any external interference in other nations’ internal affairs under any pretext” when asked about US President Donald Trump’s comment that Iran’s new leader “won’t last long” without his administration’s “approval.”

"Iran's sovereignty, security and territorial integrity should be respected," said Guo, reiterating China's call for an immediate end to the military conflict and resuming dialogue.

Russian President Vladimir Putin sent a congratulatory telegram to Khamenei on his appointment as Iran's supreme leader, the Kremlin said.

"Now, when Iran is confronting armed aggression, your work in this high office will undoubtedly require great courage and dedication. I am confident that you will honorably continue your father's work and unite the Iranian people in the face of severe trials," the statement said.

More than 1,200 people have been killed and over 10,000 others injured in US and Israeli attacks on Iran since Feb. 28, according to Iranian authorities.

Iran has retaliated with drone and missile strikes targeting Israel, Jordan, Iraq and Gulf countries that are home to US military assets.