Baghdad (CNN) -- At least 29 people were killed and more than 120 others wounded in a dozen car bomb explosions in Baghdad and Kirkuk on Wednesday, police said.
In Baghdad, 10 car bombs exploded in the predominately Shiite neighborhoods, killing 24 people and wounding 110 others Wednesday evening.
The 10 car bombs exploded within two hours in the Baghdad communities of Kadhimiyah, Sadr City, Saidiya, Mashtal, Baghdad al-Jadida, Al-Husseiniyah and Zafraniyah.
Two car bombs exploded in the oil-rich and ethnically mixed city of Kirkuk, about 240 kilometers (149 miles) north of Baghdad. The blasts killed five people and wounded 10 others Wednesday morning, police said.
These attacks came amid growing tensions between Sunnis and Shiites, especially after an incident in Hawija in Kirkuk province, where Iraqi security forces raided a site used by Sunni protesters to demonstrate against the Shiite-led government. A clash between security forces and gunmen last month killed at least 50 people and wounded more than 85 others.
Sunnis, who comprise a minority of Iraqis, had clout during the Saddam Hussein era but have been politically marginalized since his overthrow. Shiites, who make up a majority of Iraqis, now dominate the government.
Since December, tens of thousands of demonstrators have taken to the streets of predominately Sunni provinces -- including Anbar, Nineveh, Salaheddin and Diyala -- demanding that the Shiite-led government stop what they call second-class treatment of Iraq's Sunni community.
Such turnouts include protests at al-Atisam Square in Hawija.
More people died violently in Iraq in April than in any other month since June 2008, the United Nations said.
A total of 712 people died and 1,633 more sustained injuries "in acts of terrorism and acts of violence," the UN Assistance Mission for Iraq said.
Civilians made up most of the fatalities, 595 in total. They were also the vast majority of injured, numbering 1,438. Baghdad saw the most deaths with 697 fatalities.
CNN's Michael Martinez contributed to this report.