BAGHDAD, May 11 (Xinhua) -- The Islamic State (IS) group on Wednesday claimed responsibility for the massive car bomb explosion in eastern the Iraqi capital of Baghdad that killed 64 people and wounded 87 others, the group said in an online statement.

One of the group's suicide bombers detonated his car bomb in the predominantly Shiite district of Sadr City, leaving nearly 70 killed and some 100 wounded, according to the statement, of which the authenticity could not be independently verified.

Earlier in the day, an Interior Ministry source told Xinhua that a massive blast occurred in the morning when a booby-trapped car went off at a popular outdoor market in the Shiite bastion of Sadr City district, killing up to 64 people and wounding 87 others,  many of whom were women and children.

The explosion destroyed many stalls and civilian cars and caused damage to several nearby shops and buildings, the source said.

The IS has frequently targeted areas where crowds of people gather, including markets, cafes and mosques across Iraq.

Iraq is currently witnessing a wave of violence since the IS group took control of parts of Iraq's northern and western regions in June 2014.

Earlier, a report by the UN Assistance Mission for Iraq estimated that 741 Iraqis were killed and 1,374 others wounded in acts of terrorism, violence and armed conflict in April across Iraq.