Twin suicide bombers killed three people and wounded more than 15 at the Ali al-Baya mosque, another Shia place of worship in western Baghdad, as the faithful were about to leave weekly Friday prayers, hospital and police sources said.
In the third incident, three people, including a child, were killed and five wounded in a blast apparently targeting a police station, but struck outside a cafe in north-west Baghdad's predominantly Shia Shula district.
Two Iraqi soldiers were killed and four civilians wounded in a suicide attack targeting Shia pilgrims waiting at an army checkpoint between Mahmudiyah and Latifiyah, south of Baghdad, police said.
"A suicide bomber in a car drove at the checkpoint where there were pilgrims going to Karbala, killing two soldiers and wounding four civilians," Captain Hassan Awad Amari said.
A Shia Turk man was killed in a bomb blast close to a mosque in the northern city of Kirkuk, police said.
The man went to move a bag that had been placed on a car blocking the road to the mosque and it exploded.
Eight people were killed and another 13 wounded on Friday night when a suicide bomber struck a Shia mosque in Iskandariyah, 60km south of Baghdad, in the sixth anti-Shia attack of the day, an Interior Ministry source said.
"Eight dead bodies have been brought to our establishment and 13 wounded have been admitted, said Dr Mohammed Dia, director of the hospital in Hilla, 100km south of Baghdad.
Earlier, an Interior Ministry source had said seven people were killed and 10 others wounded when a suicide bomber slammed his car into the Al-Hadi mosque.
Twelve Iraqis and two US soldiers died in violence not obviously aimed at Shias elsewhere in the country since Thursday evening.
Most of the violence targeted Iraqi security forces north of Baghdad, while south of the capital the bodies of two sons of Najaf's police chief were found.
"The bodies of Haidar and Baha al-Jazaeri were found at 10 am in Hindiya district, 10km north of Karbala," a police source said. "The two bodies had their hands tied and were riddled with bullets."
North of the capital, an army officer was shot dead as he bought petrol, the army said.
"Unknown armed assailants on Friday opened fire on officer Baha Yunes as he was filling up at the Baquba black market," 60km north-east of Baghdad, Mohammad Moqdad said.
"Yunes was killed and three civilians, including a five-year-old child, were wounded," he added.
An Iraqi soldier died and five others were wounded in a bomb attack on Friday morning east of Samarra, 120km north of Baghdad, police said.
Another soldier was killed and one wounded in a mortar attack on their base near Dhuluiya, 70km north of the capital, the army said.
Three civilians were killed and a child wounded in a roadside bomb blast north of Samarra, police said.
Meanwhile, bodies of four Iraqis were found at Makhul, near Baiji, 200km north of Baghdad, police said.
The dead had their hands tied and each had been killed by a bullet to the head.
Identity papers found on the bodies showed they worked on a US base and a pamphlet claiming responsibility was also found, signed by the Horror Brigades of the Secret Islamic Army in Iraq, Police Lieutenant Colonel Hassan Salah Janabi said.
The US military said one of its soldiers had been shot dead in Mosul on Thursday, and another killed in a bomb blast north of the capital on Friday.
Two insurgents died and another was wounded when a bomb they were planting detonated prematurely, the US military said.
The bomb exploded "along a coalition forces main supply route at about 6:00 pm" on Thursday, a statement said.
The wounded man was detained and taken for medical treatment, the statement issued by the US forces in Tikrit said.