Denial and deception (D&D) is a core component of Iranian military doctrine, and Iran uses D&D techniques extensively to reduce the vulnerability and increase the survivability of its military forces. To apply these techniques across the military, Tehran has established what it calls a “passive defense” doctrine. The effort was based on lessons learned from past military conflicts, including U.S. operations in the Middle East and the 2006 Israel-Hizballah conflict. Key Iranian passive defense measures include camouflage and concealment, force dispersals, underground facilities, and highly mobile units. For example, Iran configures some military vehicles to resemble civilian trucks….Iran has the largest underground facility (UGF) program in the Middle East. Based on the central pillars of Iran’s passive defense doctrine, Tehran has invested heavily in constructing UGFs to conceal and protect critical military and civilian infrastructure throughout the country. Iran designed and built these facilities to support various aspects of its defense industries, key nuclear infrastructure, and military forces, including naval sites, missile bases, and equipment storage.