The United States Marshals Service (USMS) is a U.S. federal law enforcement agency within the U.S. Department of Justice (see ). The Marshals Service is the oldest American federal law enforcement agency. The U.S. Marshals office was created by the Judiciary Act of 1789. The Marshals Service is part of the executive branch of government, and is the enforcement arm of the U.S. federal courts. The Marshals Service is the primary agency for fugitive operations, responsible for prisoner transport, the protection of officers of the court, and for the effective operation of the judiciary. The Marshals Service operates the Witness Protection Program, and serves federal level arrest warrants.