Unidentified gunmen shot and killed Ayatollah Mamousta Borhan Ali in front of his home in early September in the western city of Sanandaj in Kordestan. The cleric was a leading supporter of Iranian President Mahmoud Ahmadinejad's campaign for re-election in June.
His assassination follows an earlier attempt on the life of a provincial judge in the city.
Iranian Interior Minister Mostafa Mohammad Najjar said top security and military officials held a special session to examine the volatility in the Kurdish province.
Najjar added local police were embarked on effort to find and arrest those behind the assassinations, state-funded broadcaster Press TV reports.
Mohammad Taghi Heydari, the governor in Sanandaj, said the assassination was part of an external plot to portray the region as volatile and unsafe.
Iranian media reports only identified "foreign elements" as the alleged perpetrators.