Al-Qaeda's front group in Iraq said on Friday that it carried out a wave of bombing and shooting attacks across the country that killed 42 people.

The group said Thursday's attacks, which hit six different provinces and left more than 250 people wounded, targeted security forces in response to "torture and killings against Sunnis".

"The government of the Green Zone ignored warnings to stop the torture and killings against Sunnis, and they did not show any readiness to respond to these warnings," the statement posted on a jihadist forum said, in a derisive reference to the heavily fortified area where the Iraqi government is based.

"In response to these crimes, the ministry of war of the Islamic State of Iraq launched a new wave of invasions through its security apparatus.

"These operations took place simultaneously against targets chosen with precision, including security headquarters and military patrols which are part of the Safavid project."

Sunni insurgents often invoke Iran's Safavid past, referring to the Shiite dynasty that ruled Persia between the 16th and 18th centuries and conquered part of Iraq, when denouncing the Baghdad government, which they say is controlled by Iran.