Iran "strongly condemned" a Swedish court's life sentence for a former Iranian official involved in the deaths of thousands of political prisoners in the 1980s.

Earlier on Thursday, Stockholm's district court found Hamid Nouri guilty of "murder" and "serious crimes against international law."

The spokesperson for the Iranian Foreign Ministry, Nasser Kanani, said the ruling was political and based on "fabricated allegations" at a court which "lacked qualification." He accused the Swedish judicial system of "submission to the propaganda machine" of the Mujahedin-e-Khaleq (MEK), a foreign-based opposition group designated by Tehran as a terrorist entity.

The ruling was the first ever in the case of the mass executions, and followed a 30-month trial that saw a plethora of testimony by former inmates recounting their ordeal at Gohardasht prison outside the Iranian capital, Tehran. Nouri, according to those accounts, was a deputy prosecutor who would march death row inmates to the gallows. Claiming a different identity and occasionally smiling, the 61-year-old defendant, persistently denied the charges.