to four. It had shifted to fully manned units from its prior reliance on the mobilisation of reserve soldiers to flesh out a larger number of units manned at a lower level. Each brigade had three infantry battalions and one lightly equipped artillery battalion. Armoured forces consisted of one tank brigade. Artillery forces were increased from one to three regiments during the 1980s, and six battalions of coastal artillery were maintained at strategic points along the Adriatic Sea littoral. Post 1991 In 1992, the Library of Congress estimated that the ground forces had about 35,000 men, or about three-quarters of all armed forces personnel. Because the strength of the ground forces was sufficient to man only about two divisions, brigades of approximately 3,000 soldiers became the largest army formation. In 1991 four infantry brigades constituted the bulk of combat units in the ground forces. During the civilian riots in 1997, the political attempts by the government to use the Armed Forces to crush the rebellion were soon demonstrated to be a failure, following a total disintegration of the Armed Forces and the looting of the military facilities by the civilian population. Albania sheltered many thousands of Kosovar refugees during the 1999 conflict, and allowed NATO to provide logistical assistance for Kosovo Force (KFOR) troops through Communications Zone West headquartered in Durrës. Albania was part of the International Stabilization Force (SFOR) serving in Bosnia (then EU mission ALTHEA), and Albanian peacekeepers are part of the International Security Assistance Force in Afghanistan, ISAF and the international stabilization force in Iraq. Albania has been a steadfast supporter of U.S. policy in Iraq, and one of only four nations to contribute troops to the combat phase of Operation Enduring Freedom. Increasing the military budget was one of the most important conditions for NATO integration. Military spending has generally been lower than 1.5% since 1996 only to peak in 2009 at 2% and fall again to 1.5%. There was an incident in 2002 in Albania where it was discovered, in a cluster of mountain bunkers, 16 tons of primitive, undocumented chemical weapon agents that Albania had forgotten about. In December 2006, the Armed Forces adopted a new structure based on the Joint warfare concept. It had three main Commands: the Joint Forces Command, the Joint Support Command and the Training and Doctrine Command. The Albanian Joint Forces Command (AJFC) consists of the Rapid Reaction Brigade,