Violence in Iraq has left at least 23 people dead, with attacks on civilians outside a Shia mosque and in a bakery in a mainly Shia part of Baghdad.
The killings contrast with earlier attacks targeting security forces
A bomb in Baghdad also killed one US soldier as US Defence Secretary Donald Rumsfeld made a surprise visit to Iraq to inspect training for local forces.
Iraqis had to take the lead eventually in fighting the militants, he said.
A BBC correspondent suggests Friday's attacks may have been aimed at igniting sectarian violence among Iraqi Muslims.
The new killings contrast with attacks on Iraqi security forces earlier this week, says Jon Leyne in Baghdad.
Attack after prayers
A bomb went off outside the mosque in the town of Balad Ruz as worshippers were leaving after Friday prayers, killing at least 13 and injuring up to 40.
Armed families took away bakery victims for burial
Three children are believed to be among the victims, as well as a number of Iraqi National Guard troops.
According to witnesses, the bomb was hidden in a lorry carrying vegetables parked in front of the mosque. It went off when Iraqi troops approached it.
The attack on the Happiness Bakery took place in the Amin area of Baghdad, a predominantly Shia neighbourhood.
Gunmen killed at least nine people in the attack, shouting "God is great", a witness told Reuters news agency.
Police suggested a tribal dispute may have triggered the attack, in which a police station opposite was not touched, but local people blamed Sunni extremists.
"It's the Wahhabis who came to sow terror," Abu Fatima, a neighbour, told AFP news agency.
US officials gave no details of the attack in Baghdad which killed one American soldier.
US Defense Secretary Donald Rumsfeld made his eighth visit to Iraq on Friday before returning to Europe where he has been having security talks with Nato colleagues.
In an address to US troops upon landing at the Mosul airfield, he said they had shown "that America is in fact a land of liberators, not a land of occupiers".
But he underlined the importance of local security forces in taking control of the situation: "It is the Iraqis who have to, over time, defeat the insurgency."
Mr Rumsfeld was speaking hours after 10 Iraqi police were killed during a fierce gun battle late on Thursday in Salman Pak, south-east of Baghdad.
He was due to attend an international security conference which opened in the German city of Munich on Friday.