(Adds details on attacks, paragraphs 4-5)
BAGHDAD, July 29 (Reuters) - Attackers killed at least 12 people and wounded 31 in a series of shootings and explosions across Iraq on Thursday, security and hospital sources said.
In Baghdad, gunmen threw a hand grenade at an army vehicle in the mainly Sunni district of Adhamiya, killing three soldiers and setting the car ablaze, city security spokesman Major General Qassim al-Moussawi told Reuters.
When chased by police and soldiers, the attackers threw three more grenades, killing three policemen and wounding ten people, he said. "We are still searching for the attackers in the Adhamiya district," he added.
An Interior Ministry source put the Adhamiya death toll at 16. The source said gunmen killed three soldiers using silenced guns. While police and civil defence crews rushed to the scene, five roadside bombs exploded within a radius of one kilometre, killing three civilians and wounding 14, among them seven policemen and civil defence workers.
It was not immediately possible to reconcile the varying reports on the Adhamiya violence.
In Falluja, 50 km (32 miles) west of Baghdad, the scene of heavy fighting with U.S. forces in the past, a roadside bomb targeting an Iraqi army patrol killed three soldiers and wounded four others in a northeast district, a police source said.
In a separate incident, another roadside bomb went off near an Iraqi army patrol, wounding five soldiers in Falluja.
And in Shirqat, 300 km (190 miles) north of Baghdad, a suicide car bomber targeting an Iraqi army base killed three soldiers and wounded eight, army and police sources said.
The U.S. military is reducing its forces in Iraq to 50,000 troops by Aug. 31, when they will formally move to a more advisory role supporting Iraq's security forces.
There are just under 65,000 troops left, Admiral Michael Mullen, Chairman of the Joint Chiefs of Staff, told reporters in Baghdad on Tuesday.
Sunni Islamist insurgents have sought to exploit the power vacuum after inconclusive parliamentary elections in March.
There have been almost daily bombing and shooting attacks in which hundreds of Iraqis have died, although overall violence has dropped sharply since 2006-07, when thousands of Iraqis were killed in sectarian bloodletting. (Reporting by Baghdad newsroom; Writing by Ulf Laessing; Editing by Mark Heinrich)
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