An Iranian student leader has died in jail while on a hunger strike to demand his release.
Mr Mohammadi was recently taken back into custody
Akbar Mohammadi was first arrested in 1999 after clashes between the security forces and students at Tehran University.
He was freed last year but was recently rearrested and began his fast.
Authorities say they are investigating the cause of his death. They say Mr Mohammadi was under the care of a doctor in jail.
"He was under intense supervision by the prison physician.
Last night his health condition deteriorated," Justice Minister Jamal Karimirad told Reuters news agency.
"He insisted on going back to his cell. His condition weakened again there and he died on his way to the hospital," he said.
Mr Mohammadi's lawyer, Khalil Bahramian, complained that he was not granted access to his client in jail.
Mr Bahramian said he had wanted to see him to persuade him to stop the hunger strike.
"This is a violation of international conventions and Iran's Islamic laws," he said.
Mr Mohammadi was initially sentenced to death for his role in anti-government protests, but it was later commuted to 15 years in prison.