Several car bombs struck the oil-rich northern city of Kirkuk in a two-hour span on Saturday, killing four people and wounding 30.
Police said the attacks started about 9:40 am when a car packed with explosives blew up near the offices of the Kurdish Democratic Party of Massoud Barzani, leader of Iraq's autonomous Kurdish region.
At least two people were killed and 30 wounded, including five KDP guards, in that blast in eastern Kirkuk, police said.
Another car bomb exploded about 20 minutes later near a girls' school in the south of the city, but the facility was closed for the weekend and no casualties were reported.
A third car bomb hit a gas station at 10:10 am in Kirkuk, wounding three civilians, followed by two other parked car bomb in a commercial area about 20 minutes after that in the southern half of the city.
A sixth car bomb exploded elsewhere in southern Kirkuk at 11:50 am, while two roadside bombs targeted police patrols at about the same time in a predominantly Christian area in the north of the city.
Also on Saturday, a bomb in a parked car struck a commercial area south of Baghdad, killing a civilian and wounding eight, police said.
The explosion occurred just before 8am in Mahmoudiya, 30km away from the capital.
Police said some shops were damaged and four vehicles caught fire.
The deaths of the two US soldiers on Friday raise to at least 3,094 the number of US soldiers killed since the Iraq war started in March 2003, an Associated Press count said.
Ten US troops were killed in the first three days of February, according to the military, including two who died in a helicopter crash northwest of Baghdad on Friday.