Iran's former prime minister Mir Hossein Mousavi, who was the focus of a 2009 mass protest movement and has spent the last 15 years under house arrest, has been hospitalized after his health deteriorated, an advisor said on Friday.
Mousavi, the last person to serve as Iran's premier before the post was abolished, had claimed to be the rightful victor of the disputed 2009 presidential elections.
Most recently, he urged Iran's clerical leadership to step down because of its deadly crackdown on protesters in January in which many thousands were killed.
Last week, "he suffered a health crisis and was transferred to a hospital," his advisor Ardeshir Amir Arjomand, who is based outside Iran, told BBC Persian.
"He is now hospitalized, although his condition has improved since today," he added.
Arjomand said Mousavi's condition had been affected by being moved to a new location when his previous residence in central Tehran was damaged in the US-Israeli strike on February 28 that killed supreme leader Ali Khamenei.
Mousavi, 84, and his wife Zahra Rahnavard, 80, also under house arrest since 2011, had been living on Pasteur Street close to Khamenei's offices.
"They remain in a state of uncertainty and displacement. They were previously under pressure, and now it has increased further," said Arjomand in the interview.
"It is unclear how many more times they must go through such crises before officials realize that they should be released," he added.
The Iranian news site Avash said on Thursday that Mousavi was suffering from a serious heart condition and his family were unhappy over the lack of attention from authorities. Unconfirmed reports on Friday said the health ministry had pledged to closely follow his condition.
Mousavi claimed to have won in 2009 against incumbent Mahmoud Ahmadinejad, arguing that the hardliner's victory was rigged and sparking vast protest rallies in his support known as the Green Movement.
Earlier this year, he said the crackdown on January's protests was a "black page in the history of our nation", a "great betrayal and a crime".
Mousavi was prime minister from 1981 to 1989 under the presidency of Khamenei, who became supreme leader after the death of revolutionary founder Khomeini.
Even in the 80s, Khamenei viewed Mousavi as a rival, with the then-premier regarded as a more moderate figure within the system.
