And, drive-by shootings and suicide bombings killed at least eight Iraqis, including a senior Industry Ministry official and a top Shi'ite cleric.
The attacks came the day US Secretary of State Condoleezza Rice made a surprise visit to Iraq to meet leaders of the new national government and to urge patience for Iraqis weary of repeated bombings and insecurity.
US marines said a seven- day offensive near the Syrian border to wipe out supporters of Jordanian-born militant Abu Musab al-Zarqawi ended late last night, killing more than 125 insurgents, wounding many others and detaining 39 "of intelligence value."
Nine US marines were also killed and 40 injured during Operation Matador, one of the largest US campaigns since militants were driven out of their Fallujah stronghold in November.
Unconfirmed reports said that al-Qaida ally Abu Musab al-Zarqawi had been wounded in the fighting.
The assault came amid a surge of militant attacks that have killed over 450 people in just over two weeks since Iraq's first democratically- elected government was announced. Insurgents continued launching attacks in a campaign apparently aimed at inflaming sectarian tensions, destabilising Iraq's new government and forcing US-led forces out.
Gunmen in two cars shot dead Industry Ministry official Colonel Jassam Mohammed al-Lahibi and his driver in western Baghdad's Ghazaliyah neighbourhood.
A leading Shi'ite cleric, Sheikh Qassim al-Gharawi, and his nephew were shot dead in another drive-by shooting, this time in the capital's New Baghdad neighbourhood.
Mr al-Gharawi was an aide to Iraq's top Shi'ite cleric, Grand Ayatollah Ali al-Sistani, and responsible for conveying Mr al-Sistani's edicts to Shi'ites in parts of Baghdad.
Three batches of men, most bound and blindfolded, were found shot in the head in Baghdad and locations south and west of the capital. Police in eastern Baghdad's impoverished Sadr City discovered 13 slain men, most appearing to be aged in their 20s with three heavily bearded, lying face down in a grave. Locals said they saw people in a truck dump the bodies onto the ground early yesterday and cover them with soil.
Police made a similar discovery late on Saturday night in Huqoul, a town in the Latifiyah area, about 25 miles south of the capital.
The bodies of 11 men with their hands tied behind their backs and fatal bullet wounds to the head were found dumped in a deserted chicken farm. Latifiyah is in an insurgent stronghold known as the Triangle of Death. The region has been the scene of tit-for-tat killings between Shi'ite and Sunni Muslim groups.
In the battleground city of Ramadi, 70 miles west of Baghdad, the slain bodies of 10 Iraqi soldiers were found. Their bodies had been dumped in eastern Ramadi's Abu Obeid area.
In downtown Baqouba two explosions detonated about five minutes apart in a busy street as residents were heading to work, killing four and wounding 37.
"Yes, the insurgency is very violent, but you can beat insurgencies not just militarily," Ms Rice told reporters in her first stop in the Kurdish town of Irbil.
"You can beat them having a political alternative that is strong," and in which all Iraqis are invested, she added. The one-day trip was her first visit to Iraq as the US's top diplomat.
The US military said that its latest operation in Iraq, involving 1,000 marines, soldiers and sailors, had neutralised a desert sanctuary near the Euphrates River used by insurgents, who the military said relied on ancient smuggling routes across the Syrian border to bring foreign fighters into Iraq.