An Iranian official has rejected online rumors that Supreme Leader Ayatollah Ali Khamenei is gravely ill, saying that the 81-year-old cleric was going about his business as usual.

“By the grace of God and with the good prayers of devotees, the gentleman (Ayatollah Khamenei) is in good health and is busy vigorously carrying out his plans according to his routine,” Mehdi Fazaeli, an official with an office tasked with publishing the supreme leader’s works, tweeted on December 7.

The tweet followed reports by foreign news outlets that a visit between Khamenei and President Hassan Rohani had been canceled and the supreme leader’s duties handed over to one of his sons, 51-year-old Mojtaba Khamenei, who has no political position.

Ayatollah Khamenei was reportedly last seen in public on November 24, the date of his official Twitter account’s last post.

Khamenei is the longest-serving head of state in the Middle East, having been Iran’s supreme leader since 1989. Prior to his election to the position, which gives him a say in all matters of state, Khamenei was Iran’s president from 1981 to 1989.

In 2014, Khamenei underwent successful surgery for prostate cancer.

On December 7, the IRNA state news agency blamed a fall in Tehran’s bourse index on an unidentified “rumor.”

According to Iran’s Tasnim news agency, the rumor of Khamenei’s declining health started with a “fake” tweet in Arabic attributed to a “separatist individual based in London.”

State television has denied that a meeting of the Assembly of Experts, a body of clerics that is empowered with selecting the supreme leader, had convened.

Tasnim said that an image of the purported meeting circulating on social media was “fake.”

With reporting by AP and Reuters