Updated

An Al Qaeda-affiliated group in Iraq claimed responsibility on Wednesday for bloody attacks that killed dozens of people across the country a day earlier.

In a statement posted on a militant website, the Islamic State of Iraq said the car bombs and other explosions came to avenge the executions and "massacres" of convicted Sunni inmates held in Iraqi prisons.

Most of the nearly 20 attacks on Tuesday, the eve of the 10th anniversary of the 2003 U.S.-led invasion, targeted Shiite areas in Baghdad.

They killed 65 and wounded more than 200, demonstrating in stark terms how dangerously divided Iraq remains more than a year after American troops withdrew.

The Al Qaeda statement warned the Shiite-led government to stop executing Sunni prisoners or "expect more bad events ... and seas of blood."

"What has reached you on Tuesday was the first drop of rain, and a first phase ... that will be followed by more revenge," it said.

Also on Wednesday police said a car bomb exploded during rush hour in eastern Baghdad, killing two civilians and wounding four.

A medical official in a nearby hospital confirmed the casualty figures. All spoke on condition of anonymity as they were not authorized to release information.

Violence has ebbed sharply since the height of insurgency, but militants are still able to stage high-profile lethal attacks.