In Baquba, an explosion in a restaurant on Saturday killed seven people, including three police officers, an Iraqi army officer said.
"Seven people, including three policemen, were killed and at least five other people were injured around 2pm (1000 GMT) in an explosion at a restaurant near the courthouse in the centre of Baquba," Colonel Ismail Ibrahim said.
He did not know whether the blast, which destroyed the back of the restaurant, was caused by a bomb inside the establishment or on a booby-trapped car outside.
Baquba, 60km north of Baghdad, is a mixed Sunni-Shia town where fighters have been active.
Elsewhere, eight people, including a Turkish truck driver and a US soldier, were killed in attacks.
One Iraqi civilian was killed and three wounded in a car bombing on Saturday against a US-guarded convoy in western Baghdad, an Interior Ministry source said.
In the northern Iraqi city of Mosul, an Iraqi civilian was wounded when a car bomber detonated his explosives near a US military convoy, said security sources, the sixth such car bombing in the city in two weeks. The bomber also died in the attack.
There were several suicide
attacks on US military convoys
South of Mosul, a Turkish driver was killed in a roadside bombing, police said, bringing to eight the number of foreign truck drivers, most of them Turks, killed in attacks in northern Iraq since the start of the year.
In another incident involving foreigners, two Filipinos - a man and a woman - were slightly hurt when fighters fired at their minibus as they headed for Baghdad airport where they worked at a duty-free shop, police said.
US soldier killed
Last year, the Philippines pulled its token military contingent from Iraq after fighters threatened to behead a Filipino truck driver, but many Filipino civilians continue working in Iraq, and a Filipino has been held captive by fighters since November.
In other violence, a US soldier died on Friday of wounds suffered in a mortar or rocket attack near Tikrit, north of the capital, the military said.
A police officer and an Iraqi soldier were killed in separate incidents in the northern oil centre of Kirkuk, security officials said.
Three Iraqi policemen and five
civilians were killed in Baquba
Another police officer was killed overnight by a bomb in Tuz, near Tikrit, while a member of an oil-protection force was killed in a clash with suspected fighters in Baiji.
An Iraqi soldier was killed and another wounded overnight in an explosion near Samarra, north of Baghdad, and four civilians were wounded in a car bomb attack at dawn on Saturday in the same area against an Iraqi army convoy.
The Iraqi army, meanwhile, said it had arrested 20 people in Khalis, north of Baghdad, on suspicion of carrying out attacks against Iraqi forces.
Australian soldiers that are part of an additional troop commitment to Iraq began leaving from the northern Australian city of Darwin on Saturday.
An advance party of 43 troops flew out on Saturday afternoon, as part of a larger contingent totalling about 450 soldiers that will boost Australia's troop commitment in Iraq by 50%. Additional equipment and supplies will also leave on Sunday.
Australia, a close ally of the United States, sent about 2000 military personnel to Iraq and the Middle East at the start of the US-led war in Iraq.