In a statement the company said, “We have asked the Defense Department’s inspector general’s office to examine possible inappropriate contact between our former employees and two subcontractors before some contracts were awarded.”

“The inspector general’s office may investigate whether these two employees may have solicited and/or accepted payments from these third-party subcontractors while they were employed by us,” it added without elaborating further.

According to Halliburton spokeswoman Wendy Hall, the firm has already taken the necessary steps.

“The company has terminated its relationship with the subcontractors [and] we are doing everything we can to make sure this particular scenario doesn't happen again,” said Hall.