The contractor was employed by Kellog, Brown and Root, a subsidiary of Halliburton, a Houston-based oilfield services and construction company.
The explosion occurred 50 km north of Tikrit, ousted Iraqi President Saddam Hussein’s hometown.
Halliburton is the former company of US Vice President Dick Cheney which has major contracts for reconstruction in both Afghanistan and Iraq.
In the central Iraqi town of Fallujah, at least two occupation soldiers were injured when a rocket-propelled grenade was fired at the police station.
After the attack, a crowd of Iraqis gathered chanting slogans in support of Hussein. A mine planted on a bridge in the same town, 50 km west of the capital, exploded as four US military vehicles were passing, lightly damaging one, according to witnesses.
Meanwhile, American troops have stirred up more resentment after insisting on the appointment of a female judge in the manly Shi'i city of Najaf.
Local Islamic clerics have protested the appointment. The final decision is now left to Iraq’s Grand Ayatollah, who will rule on the case next month.