An Iraqi guard outside the compound, also home to KBR, a subsidiary of the US oil services giant Halliburton, said a 4WD vehicle was destroyed when a bomb planted near a blast wall exploded 100 metres from the main gate on Saturday.
One of the three people inside the car was killed and two others wounded by the bomb, the guard said, refusing to give his name.
A spokeswoman for the British-led force in southern Iraq could confirm only that there was an explosion at 1205 GMT in Basra.
According to the witness, the two killed were travelling in a vehicle at the time of the blast.
Late on Friday a car bomb exploded outside a Baghdad church, shattering stained glass windows but harming no one, the church priest said.
"Nobody was injured, thank God," Uwaida Wahba told Reuters. "It was a cowardly act."
The twisted and charred wreckage of the car lay outside the Sabbatarian Adventist Church in central Baghdad. Services due to be held on Saturday morning had been cancelled, Wahba added.
No one has claimed responsibility for the blasts.