The Justice Department filed a lawsuit Thursday against defense contractor Kellogg, Brown & Root in federal district court in Washington, D.C., alleging the company improperly billed the government for armed security guards.

The complaint alleges that Houston-based KBR violated the False Claims Act through certain billings made to the Army under the company’s Logistics Civil Augmentation Program III contract. The contract, according to the Justice Department’s complaint, covers services that include food, transportation and laundry for military operations in Iraq. The complaint does not identify a dollar amount loss to the taxpayers. The 13-page complaint alleges, among other things, unjust enrichment and breach of contract.