A series of car bombs killed at more than 20 and wounded over 100 others, in Baghdad Sunday morning the New York Times reports.

According to the Associated Press, car bombs were detonated in multiple outdoor markets around the capital city with the Shi’ite dominated city of Sadr hit the hardest with four explosions.

The cities of Ameen, Habibiya, Husseiniya, Kamiliya and Karrada were also targeted. Authorities say casualty numbers could have been higher but police were able to defuse at least one of the planted explosives.

No group has claimed responsibility for the attack, as of yet though many believe Sunni extremist groups such as the Al-Qaida local affiliate to be the culprit.

Official’s say they worry that sectarian violence will mount as provincial elections near on April 20.  The vote will be the first to take place a year after the US troop removal.

This is the third time this month that acts of terrorism have killed more than 20 people in Iraq in a single day.