But the toll may rise as ambulances continued to bring in injured to hospitals in the capital, according to Health Ministry spokeswoman May Abd Al-Karim on Wednesday.
No one has claimed responsibility for the attack and Iraqi police have not commented on the situation.
Aljazeera sources report that a number of US military vehicles have also been destroyed in Baquba, injuring a number of occupation soldiers.
Meanwhile, six people were reported killed and 15 more wounded overnight when British forces pounded Shia militia positions in the southern city of Amara.
It was the first operation of its kind since Thursday, when heavy fighting broke out further north in Najaf between Shia leader Muqtada al-Sadr's Al-Mahdi Army and US-backed Iraqi forces.
Shia resistance may end relative
quiet in the UK-controlled south
Fighting began late on Tuesday when British tanks tried to cross a bridge into the city. Starting at midnight local time and lasting three hours, British jets bombed three districts of the city where militiamen are believed to be holed up, damaging six houses and cutting off electricity supplies.
Six people were killed and 15 were wounded overnight, said the director of the al-Zahrawi hospital.
British spokesman Major Ian Clooney responded, "There was appropriate force in a very targeted and precise manner. The exact number of insurgent casualties is not known."
The operation was carried out in consultation with Iraqi authorities and leaflets were air-dropped to inform residents of damage caused by resistance activities, Clooney said.
British forces also used tear gas in the southern Husayn neighbourhood, according to witness Saad Kadhim Muhammad.