Two car bombs ripped into a busy intersection and a public square in Baghdad on Tuesday, killing at least 19 people a week after a wave of deadly bombings highlighted Iraq's struggle with militant groups.

Clouds of dark smoke rose above the center of the capital where the bombs exploded just minutes apart, leaving dead and wounded lying in the street and slumped inside a damaged minibus, witnesses and police said.

Violence in Iraq has coincided with intensifying bloodshed in neighboring Syria, where Iraqi officials warn some Sunni Muslim insurgents are heading, and with calls by al-Qaida's local Iraqi affiliate for a renewed campaign of attacks.

Three young men in blood-stained T-shirts searched for a friend near the wreckage of one of Tuesday's blasts in Baghdad and women in traditional abaya gowns screamed out the name of a missing relative, a Reuters reporter at the scene said.

"We were in a patrol when we heard the first explosion. The second explosion hit another square, and we went to help... There was a minibus with six dead passengers inside it," said Ahmed Hassan, a police officer.

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The explosions followed attacks and bombings in Baghdad and across the country on July 23 that killed more than 100 people in a coordinated surge of violence against mostly Shi'ite Muslim targets. An al-Qaida affiliate known as the Islamic State of Iraq claimed responsibility.

Wave of attacks kills more than 100 across Iraq

Violence has eased since sectarian killings reached their height in 2006-2007 when tens of thousands of Sunnis and Shiites were slain.

But insurgents have carried out a major attack at least once a month since the last U.S. troops left Iraq in December, nine years after the invasion that toppled Saddam Hussein.

US vets mix regret, detachment on Iraq violence

Al-Qaida often targets Shiite pilgrims or religious sites in an attempt to stir up sectarian tensions or to show that Iraq's armed forces are unable to protect civilians.

Last month was one of the bloodiest since the U.S. withdrawal, with at least 237 people killed and 603 wounded.

Iraq's violence often feeds into political tensions.

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Prime Minister Nuri al-Maliki, a Shiite, is fending off attempts by Sunni and Kurdish rivals to vote him out of office, threatening to scuttle a fragile power-sharing agreement.

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