BAGHDAD -- A series of car bombs in Baghdad killed at least 33 people and wounded more than 100 on Thursday, with one near the "Green Zone" diplomatic complex, fueling a death toll that has soared since the beginning of the year to levels not seen since 2008.
Militant groups, including al Qaeda, have increased attacks in recent months in an insurgency against Iraq's Shiite-led government, raising fears of a return to full-blown sectarian conflict after U.S. troops withdrew 18 months ago.
Iraqi police sources said one bomb exploded just 200-300 yards outside Baghdad's international zone, close to Iraq's Foreign Ministry, killing four and wounding 12 people.
The central zone is a highly fortified area housing Western embassies including the U.S. mission and the nearby Iraqi ministry has been a frequent target of attacks.
"Cowardly terrorists targeted unarmed citizens in seven places in Baghdad," the Interior Ministry said in a statement. It put the death toll far lower, saying only three people were killed and 44 wounded in the violence.
Since the start of the year, attacks using multiple car bombs have become an almost daily occurrence, killing scores of people in Iraq, including during a religious holiday last weekend when bombers targeted families celebrating outside.
Each of the past four months has each been deadlier than any in the previous five years, dating back to a time when U.S. and government troops were engaged in battles with militiamen.
The government has launched a security sweep to try to round up suspected militants and Prime Minister Nuri al-Maliki said on Wednesday the crackdown would continue.
The Interior Ministry described the conflict last month as "open war", although officials have since said the violence is not as severe as media reports suggest and have said they are in control of the country.
The United States has said it will work closely with the Iraqi government to confront al Qaeda and will discuss this during a visit of Foreign Minister Hoshiyar Zebari on Thursday to Washington.
Bombers targeted districts in central, eastern, northern and southern Baghdad, including Shiite areas, police said.
An attack in Baladiyat, eastern Baghdad, killed five people and wounded 17 when a car bomb exploded near a traffic police station. Pictures showed the blackened shells of cars with their roofs caved in and their wheels splayed on the ground.
"Windows were smashed and my children started screaming and running everywhere, smoke and dust filled my house," said a man wounded by flying shards of glass. He declined to be named.
"The politicians are responsible for the deterioration in security," he said.
Another attack in al-Shurta al-Rabaa district used a bomb on the trailer of a tractor carrying gas cylinders. It killed four and wounded 18, police said.
In Husseiniya, a district on the northeastern outskirts of Baghdad, three people were killed and fourteen wounded when a mini bus driver left his vehicle armed with a bomb in a repair shop.