GENEVA, March 10 (Reuters) -

The U.N. Special Rapporteur on human rights in Iran said on Tuesday he had asked Tehran to free all prisoners temporarily, saying it is "unfortunate and disturbing" to continue holding political prisoners amid the coronavirus outbreak.

Iran's judiciary chief said on Monday it had temporarily freed about 70,000 prisoners to help stem the spread of the coronavirus in jails as officials reported hundreds of new infections and dozens more deaths across the country.

But U.N. rapporteur Javaid Rehman said only those serving sentences of less than 5 years had been freed while political prisoners and others charged with heavier sentences linked to their participation in protest marches remained in jail.

"A number of dual and foreign nationals are at real risk if they have not...got it (coronavirus) they are really fearful of the conditions," Rehman told a press briefing in Geneva.

"This is also my worrying concern and therefore I have recommended to the state of the Islamic Republic of Iran to release all prisoners on temporary release...," he said. It was not immediately clear whether he meant all prisoners in the country or all political prisoners who remained in jail.

Rehman also described the pace of the spread of the virus within Iran as "highly disturbing" and criticised containment measures carried out by the authorities.

"In my estimation the state has done too little and too late," he said, in response to a question about Iran's handling of the outbreak.