Jailed Iranian labour activist, Mansour Osanloo has been moved to hospital following a critical decline in his health in prison, reports said.

Human rights media report that the head of Vahed Transit Drivers Union was taken to a hospital outside the prison for treatment of his heart condition.

In March, Osanloo’s sister, Fereshteh Osanloo reported that her brother had three blocked arteries in his heart and required immediate medical treatment.

She added that her family had repeatedly urged authorities to allow Osanloo to leave prison for the necessary medical treatment but they were turned down every time.

Osnaloo had recently participated in the collective hunger strike at Rejai Shahr Prison in Karaj to protest poor prison conditions.

Osanloo was arrested in 2007 and sentenced to five years in prison on charges of endangering national security and propaganda against the regime.

Osanloo is nearing the final months of his sentence, and the prison physicians have agreed on several occasions that his health complications should exempt him from completing his imprisonment, but the prosecutor has rejected calls for his early release.