A spokeswoman for the Air Force Space Command stated, "Air Force uses two different systems - a secure site on which classified information can be used and an unclassified site for day-to-day operations."
It also added that it had started blocking the sites in Aug 2010 to avoid having "classified incidents on our unclassified systems."
However, she assured that the sites would be unblocked once they are convinced that unclassified Air Force networks are no more under threat.
"We work diligently to use our resources in the most effective and efficient manner possible. And blocking access to the WikiLeaks' material diminishes our need to go through the labor and resource-intensive process of cleaning unclassified machines that have been compromised with classified materials," she added.