Navy Day is celebrated on 8 September to commemorate its service in the Indo-Pakistani War of 1965. The navy lost one-half of its force in the Indo-Pakistani War of 1971. The Navy heavily depended on American-built naval technology and operated a large infrastructure from 1947 to 1971. The Pressler amendment forced an embargo in the 1990s, during which the navy developed air independent propulsion (AIP) technology purchased from France and built the "Agosta"-class submarines; two of these (as well as one of the new frigates) were built at Pakistan's facilities in Karachi. The navy's surface fleet consists of helicopter carriers, destroyers, frigates, amphibious assault ships, patrol ships, mine-countermeasures, and miscellaneous vessels. Established in 1972, the Naval Air Arm provides fleet air defence, maritime reconnaissance, and anti-submarine warfare capability. Mirage 5 aircraft donated by the PAF are flown by the Navy, equipped with Exocet anti-ship missiles. The Navy's fleet of P-3C Orion turboprop aircraft, equipped with electronic intelligence (ELINT) systems, play a pivotal role in the Navy's gathering of intelligence. Since 2001, the navy has emphasised its role and expanded its operational scope across the country with the establishment of Naval Strategic Forces Command, based in Islamabad.