Six coalition soldiers have been killed and many others injured after several blasts in the Iraqi city of Karbala, military officials say.
Car bombs, grenade-launchers and guns were used in the attacks
Major General Andrzej Tyszkiewicz, who commands the Polish-led force in the area, said the attacks were co-ordinated and meant to do much harm.
Blasts hit the mayor's office and two bases used by coalition forces on the university campus.
Seven Iraqi civilians and police were killed and 80 injured, doctors said.
Bulgaria's Defence Ministry said four Bulgarian soldiers were among the dead, while 27 of its servicemen sustained injuries in Saturday's car bomb and mortar attacks.
The other two dead soldiers came fromThailand, said a spokesman for the Polish forces.
Karbala is a holy Shia city south of the capital Baghdad. Several nations have troops operating there, including Poland, Bulgaria, Thailand, the Philippines and the US.
Five of the injured were said to be in a serious condition.
City governor Akram al-Yasseri was among those injured in the blasts, the French news agency AFP reported.
The bombers' targets were coalition military bases around Karbala.
In the first attack two suicide bombers blew up their cars outside a military logistical base.
At around the same time a car bomb and mortars were used to hit the Bulgarian military headquarters in the city.
A third car bomb exploded near a military facility based on the same site as the city's main police station.
"It was a co-ordinated, massive attack planned for a big scale and intended to do much harm," Major General Tyszkiewicz said on Polish TV.
A spokesman for the Coalition Provisional Authority in Iraq, Charles Heatley, said they would not be cowed by the bombers.
"We roundly condemn these acts of terrorism which we have seen again today...
"We will not be deflected from this mission; we will stay until the job is done and not a day longer," he said.
Earlier, US military officials said American soldiers had killed four Iraqis in the northern city of Mosul after coming under attack.
The soldiers were checking for roadside explosives devices when they were fired at with rocket-propelled grenades and small arms.
US troops in and around Mosul have repeatedly come under attack in recent weeks.