In 2002, the total active armed forces of Iran numbered approximately 520,000 with reserves of 350,000. The army had 325,000 soldiers had four armored divisions and six infantry divisions. Their equipment included 1,565 main battle tanks and about 890 multiple rocket launchers. The air force had personnel numbering 52,000 and 306 combat aircraft. The navy of 18,000 had 3 frigates, 6 submarines, and 56 smaller patrol and coastal combatants. The Revolutionary Guards unit (Pasdaran) had an estimated 125,000-man army and 20,000 sailors and marines. The paramilitary had 40,000 active members of law enforcement forces including border guards. There was a reserve of the Popular Mobilization Army of around 300,000 peacetime volunteers, mostly youths. This number can swell up to 1,000,000. It is believed that Iran is developing the capability of producing nuclear weapons. The official military budget in 2000 was $9.7 billion or 3.1% of GDP.