(Adds details, background)
BAGHDAD, Jan 2 (Reuters) - A suicide bomber driving a car packed with explosives killed at least 12 people who had gathered to buy and sell cars in Iraq on Thursday, local officials said.
No group immediately claimed responsibility for the attack, which took place near the car markets in the town of Balad Ruz, in northeastern Iraq, injuring another 25 people.
However, suicide bombings are the hallmark of al Qaeda, whose Iraq affiliate has re-emerged, invigorated by the civil war in Syria and growing resentment among the country's Sunni Muslim minority towards the Shi'ite-led government.
Two years after the withdrawal of U.S. troops from Iraq, violence is at its highest levels since the sectarian bloodshed of 2006-7, when tens of thousands of people were killed.
A sticky bomb attached to a mini bus went off killing four people in the northern Baghdad's mainly Shi'ite district of Sha'ab, police said.
Earlier on Thursday, a roadside bomb exploded inside a street market killing four people and wounded another 11 in the town of Latifiya, south of Baghdad, police said.
Six more people, including three soldiers, were killed when gunmen opened fire at a military checkpoint in the same town, police said.
More than 8,000 people were killed in violent actions in Iraq last year, the United Nations said.
(Repporting by Reuters reporter in Baquba and Kareem Raheem in Baghdad; Writing by Suadad al-Salhy; Editing by Alison Williams)