An Iraqi official says his country has hanged 12 prisoners convicted of terrorism-related charges.

The Justice Ministry official said Tuesday that all of those executed Sunday were found guilty for carrying out "terrorist" attacks. The official, who spoke on condition of anonymity as he was not authorized to make public statements, didn't give further details on the charges.

Iraq has so far executed 144 people this year, compared to 129 in 2012.

Human rights groups have long criticized trial procedures in Iraqi courts, arguing that some verdicts are based on testimony obtained by torture or forced statements. The government defends the death penalty as a weapon against insurgents bent on destabilizing the country.