A car bombing at a market in central Iraq killed eight people on Wednesday and three others were murdered in Baghdad, the latest in a spike in nationwide unrest ahead of Shiite rituals.

The violence came a day after a series of attacks across Iraq killed 38 amid preparations for ceremonies on Friday to commemorate the birth of a key figure in Shiite Islam.

In Wednesday's deadliest attack, a car bombing in the town of Zubaidiyah at 9:15 am (0615 GMT) killed eight people and wounded 37 others, a security official and a medic at a hospital in nearby Aziziyah said on condition of anonymity.

The medical official said a child was among the dead, and women and children were among the wounded.

About a dozen shops were badly damaged by the bombing, a correspondent at the scene said, adding that security officials imposed a vehicle curfew on the town in the aftermath of the attack.

"It was a huge explosion this morning," said Hussein al-Zubaidi, who owns a grocery store in the market where the bombing took place.

"It was strange for us -- it is the first time this has happened in our town. We have only one ambulance, so people worked together to evacuate the victims."

In Baghdad, a series of assassinations by gunmen using silenced pistols left three people dead -- two police officers and a parliament official.

In one shooting, policewoman Ibtisam Ibrahim was killed by gunshots to the head in the east of the capital, an interior ministry official and a medic at Al-Kindi hospital said.

In west Baghdad, off-duty police first lieutenant Ahmed Swadi, who was wearing civilian clothes, was killed, the interior ministry official and a doctor at Yarmuk hospital said.

And an employee working at Iraq's parliament, Farhan Kadhim Mussa, was gunned down in the north of the capital, the interior ministry official and a medic at Medical City hospital said.

Late on Tuesday night, meanwhile, an army major was killed while leading raids on two suspected Al-Qaeda safe houses in which five alleged insurgents were detained, two security officials said.

An earlier spate of violence across Iraq on Tuesday killed 38 people, including 26 who died when a truck packed with explosives detonated in a market in the central city of Diwaniyah.

The unrest comes ahead of the culmination of Shiite commemorations to mark the birth of a central figure known as the 12th imam, with pilgrims who visit the shrine city of Karbala frequent targets of Sunni insurgents.

It follows a weeks-long spike in attacks in Iraq, with the country suffering a wave of unrest in June that left at least 282 people dead, according to a tally, though government figures said 131 Iraqis died.

While violence in Iraq has declined dramatically since its peak in 2006-2007, attacks remain common across the country.