At least 17 people were killed in separate violent attacks in Iraq's eastern province of Diyala and north of the capital Baghdad on Wednesday, police said.

Eleven civilians were killed and 15 others wounded when a roadside bomb exploded Wednesday evening near some shops in al- Mafraq area, just west of Diyala province's capital city of Baquba, some 65 km northeast of Baghdad, a police source said.

Earlier in the day, a judge and his driver were shot dead by gunmen after he left a court in the town of Siniyah, some 210 km north of Baghdad, another police source told Xinhua on condition of anonymity.

In a separate incident, Colonel Ahmed Abdul-Rahman, a traffic police officer, was killed when a bomb attached to his car detonated while he was driving his car at the entrance of the traffic police directorate in eastern Baghdad, a police source told Xinhua.

Elsewhere, a suspected al-Qaida leader was killed and one of his aides was arrested when Iraqi security forces conducted a security operation in Imam Wais area in northeast of Baquba, a provincial police source anonymously told Xinhua.

Separately, Iraqi security forces killed two gunmen and captured eight others in a pre-dawn security operation in al- Udhaim area, some 60 km north of Baquba, the source said.

Iraq is witnessing its worst eruption of violence in recent years, which raises fears that the country is sliding back to a full-blown civil conflict that peaked in 2006 and 2007, when monthly death toll sometimes exceeded 3,000.

The UN Assistance Mission for Iraq recently reported that over 1,000 Iraqis were killed and more than 2,300 wounded in acts of terrorism and violence in July, the deadliest month in more than five years.