Unknown gunmen shot dead six laborers in north of Baquba, the capital city of Diyala province on Sunday, a provincial police source said, Xinhua reported.
The incident took place in the morning when three gunmen in their car intercepted a minibus carrying the six laborers and shot them dead, the source told Xinhua on condition of anonymity.
The victims were heading to their work at a brick factory near the town of Baladroz, some 75 km northeast of Baghdad, the source said.
The incident is under investigation, the source said, adding that the attack is holding the fingerprints of Qaida in Iraq network.
Diyala province, stretching from the eastern edges of Baghdad to the Iranian border east of the country, has long been a stronghold for al-Qaida militants and other insurgent groups since the U.S.-led invasion of Iraq in 2003.