A car bomb parked in central Baghdad's Qurtaba Square exploded on Thursday, followed shortly afterwards by a second device planted on the roadside nearby, police Lieutenant Bilal Ali Majid said.
One policeman was among the dead.
In a similar attack, a bomb exploded at 7am (0400 GMT) near a Shia mosque in the Qahira neighbourhood of northeastern Baghdad. Two minutes later another bomb exploded nearby, wounding four people who had gathered at the place of the first explosion, police First Liuetenant Ahmed Mohammed Ali said.
Another four people were killed and eight wounded when a bomber on a motorcycle ran into a police patrol, Ali said. Two policemen were among the dead in the attack in eastern Baghdad.
In Samarra, 95km north of Baghdad, a bomb attack in a residential district killed a woman and wounded six other people, police Captian Laith Mohammed said.
More bodies found
In Suwayrah, 40km down river from Baghdad, authorities fished four bodies out of the Tigris that showed signs of torture.
Two of the victims had their throats cut and two others had been shot, said Hadi al-Attan, an official with the Kut morgue where the bodies were taken. All were blindfolded and had their hands and legs bound, he said.
In Diwaniya, 130km south of Baghdad, armed men broke into the city's Hamza police station, killing one policeman and freeing 10 prisoners who were being held on various criminal charges, police Lieutenant Raid Jabir said.
A number of attacks took place
in Baghdad on Thursday
The raid came at 8.30pm Wednesday, Jabir said.
Earlier on Thursday, armed men raided the offices of an Iraqi satellite channel in Baghdad and killed several guards and employees.
Reuters quoted Hasan Kamil, executive manager of Shaabiya, as saying that the assailants had stormed the station's office in eastern Zayuna district at 7am on Thursday, killing two guards and five other staff, including the office manager.
Shaabiya is a new channel which so far has only done test broadcasts, Kamil said.
Earlier, the interior ministry said eight guards had been killed in the raid.
Associated Press described the channel as "a new Sunni-Arab television station" that went on the air earlier this year, and quoted police First Lieutenant Muhammad Khayun as saying that four guards were killed in the attack.
An unknown number of armed men pulled up at the station in six cars, stormed into the offices and opened fire, then fled, police Lieutenant Bilal Ali Majid said.