Former Guatemalan dictator Efrain Rios Montt has died aged 91.

Lawyer Jaime Hernandez says the cause of death was a heart attack on Sunday.

Rios Montt seized power in a 1982 coup and presided over one of the bloodiest periods of Guatemala’s civil war as soldiers waged a scorched-earth campaign to root out Marxist guerrillas.

Rios Montt was convicted in 2013 of genocide and crimes against humanity for the massacre of 1,771 indigenous Ixil Mayans by security forces under his command.

But the ruling was swiftly set aside and a new trial ordered, dismaying human rights activists and victims who long sought to see him punished for atrocities during his 17-month regime.

He is survived by his daughter Zury Rios.