The reports said Iran's Supreme Court upheld sentences of between 15 and 20 years handed down by a court in Mahabad -- an historic centre of Kurdish nationalism -- to Reza Amini, Halmet Azarpour and Abdollah Mohammadi.

The three were members of the outlawed Iranian Kurdistan Democratic Party, the reports said. No further details were given.

Several major clashes around Mahabad were reported in July following the police shooting of a suspect. More unrest was reported this month.