Iran’s new supreme leader, Mojtaba Khamenei, is injured but “safe and sound”, the son of the president said Wednesday, offering the first official explanation for why the 56-year-old has not been seen since his appointment at the weekend.

“I heard news that Mr Mojtaba Khamenei had been injured. I have asked some friends who had connections,” Yousef Pezeshkian, who is also a government adviser, wrote in a post on his Telegram channel.

“They told me that, thank God, he is safe and sound,” added the son of President Masoud Pezeshkian.

Mojtaba Khamenei, until now a low-profile but powerful behind-the-scenes figure, was named Iran’s number one following the killing of his father, Ali Khamenei, in an air strike at the start of the US-Israeli war against the Islamic Republic.

But there had been mounting questions about his whereabouts and physical condition after his appointment by the Assembly of Experts clerical body, with the new supreme leader yet to be seen, let alone speak, in public.

State television had called Khamenei a “wounded veteran of the Ramadan war” without giving details, in reference to the conflict which broke out during the holy Muslim fasting month.

In a report on Wednesday, the New York Times, quoting three unnamed Iranian officials, said that Khamenei “had suffered injuries, including to his legs, but that he was alert and sheltering at a highly secure location with limited communication”.

There has been speculation that he was injured in the daytime air strike on a compound in Tehran that killed his father, as well as his mother and wife, on the first day of the war on February 28.

His face has appeared on giant billboards in Tehran, with one showing him symbolically receiving the national flag from his father, Ali, while the founding leader of the Islamic Republic, Ruhollah Khomeini, looks on.

Posters of him were brandished by thousands of pro-government supporters at a huge rally in central Tehran on Monday.

But night-time cries of “Death to Mojtaba!” in the capital have also underlined public opposition to a figure believed to have played a key role in repressing waves of anti-government protests since 2009.

Mojtaba’s father Ali, lived the latter half of his life with a partially paralysed arm, having been injured in an assassination attempt in 1981 blamed on the People’s Mujahedin of Iran (MEK) group.

The Iranian supreme leader position is for life and he also serves as a religious guide for Shia Muslims.