At least 22 people have been killed in a series of bombings and shootings in Iraq, security officials say.
At least 10 were killed outside a Baghdad bakery on Saturday
Fourteen people were killed in Diyala province, north of the capital Baghdad, when militants attacked two villages.
At least six people were killed by a bomb near the northern city of Kirkuk and two people were killed by a car bomb in Baghdad.
Meanwhile, a suspect in the killing of a Sunni tribal leader in Anbar province was seized, US forces said.
Sunday's violence comes a day after an al-Qaeda-affiliated group, the Islamic State in Iraq, said it would carry out a series of attacks over the holy month of Ramadan, which started last week.
About 100 militants attacked two villages in Diyala province, killing 14 people and setting fire to 12 shops.
The villagers belong to a Sunni tribe which has joined the Diyala Awakening Council, a group committed to pushing al-Qaeda militants out of the province.
At least six people were killed by a bomb at a cafe in the town of Tuz Khurmato near the northern city of Kirkuk.
The cafe was apparently serving food during the daylight fasting hours of Ramadan.
And at least two people were killed by a car bomb in Baghdad's Mansour district.
Reports quoting Iraqi police said nine more people were killed by either US troops or private military contractors who opened fire on a crowd after a sniper shot at them.
'Plot to kill leaders'
On Saturday, 10 people were killed when a car bomb exploded outside a bakery as people lined up to buy bread to break the Ramadan fast after sunset.
Meanwhile, the US military said it had captured a suspected al-Qaeda militant believed to have been behind the killing last week of Sunni tribal leader Abdul Sattar Abu Risha.
Abdul Sattar Abu Risha led Sunni opposition to al-Qaeda in Iraq
He was killed in a bomb attack near his home in the city of Ramadi, Anbar province, on Thursday.
Sheikh Abu Risha was the leader of the Anbar Salvation Council, also known as Anbar Awakening, an alliance of clans that had turned against al-Qaeda militants in Iraq.
He met US President George W Bush two weeks ago in Anbar.
The council has been working with Iraqi and US troops to push al-Qaeda fighters out of the province, once a hotbed of the Sunni insurgency against the US occupation.
A US military statement named the captured suspect as Fallah Khalifa Hiyas Fayyas al-Jumayli and said he was captured near the town of Balad, north of Baghdad, on Saturday.
"Intelligence reports indicate Jumayli is involved in a plot to kill key leaders in the Anbar Awakening," the statement said.
The US military statement said Jumayli was also responsible for "car bomb and suicide vest attacks in Anbar province, and is closely allied with senior al-Qaeda in Iraq leaders in the region".