Attacks north of Baghdad killed five people on Monday, officials said, while police found two corpses bearing signs of torture, a scene reminiscent of the country's all-out sectarian war.
The violence comes ahead of annual Shiite Muslim religious commemorations, when Sunni militants often mount attacks, and as Iraq grapples with continuing bloodshed despite wide-ranging operations targeting insurgents and tightened security.
The spike in unrest has spurred Prime Minister Nuri al-Maliki to appeal for greater cooperation with the United States in combatting militancy, and on Sunday Turkey offered to help as well.
In the northern city of Mosul, three separate shootings killed one soldier, wounded another and left two civilians dead, police and medical officials said.
Near the University of Mosul, a taxi driver was killed when a magnetic "sticky" bomb was attached to his car.
Elsewhere in the city, police found the body of a soldier in the Tigris river. The soldier had been kidnapped the previous day and had suffered multiple gunshot wounds to the head, execution-style, and his body bore signs of torture.
In Salaheddin province, north of Baghdad, police found another corpse bearing signs of torture, including some fingers having been cut off.
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During the worst of Iraq's Sunni-Shiite sectarian war in 2006 and 2007 bodies were regularly found in major rivers and along main roads, bearing signs of torture.
Also on Monday in restive Diyala province, gunmen assassinated a local official from the Ministry of Water Resources.
Attacks in western province of Anbar, meanwhile, badly damaged a power plant and left two militants dead.
Early Monday morning, gunmen seized a power plant, handcuffed the guards and bombed the facility, leaving the surrounding town of Kubaisa without electricity.
Near the former insurgent bastion of Fallujah, police shot dead two militants wearing suicide vests, including one who was driving a vehicle rigged with explosives, at the entrance to a police station.
The bloodshed is part of the country's worst unrest since 2008.
In addition to major security problems, authorities have failed to provide adequate basic services such as electricity and clean water, and corruption is widespread.
Political squabbling has paralysed the government, while parliament has passed almost no major legislation in years.