The Tariq-class destroyers are a class of guided missile destroyers of the Pakistan Navy. They were acquired from the British Royal Navy in 1993–94. The Tariqs were formerly commissioned in the Royal Navy's Surface Fleet as Type 21 (Amazon-class) frigates, a general purpose frigate in the Royal Navy. The British frigates were immediately acquired when the United States refused to renew the lease of the four and four s, due to the enforcement of the Pressler Amendment. requiring Pakistan to return the vessels to the United States at the end of their five-year lease. Upon acquisition, all six frigates were reconfigured to enhance their engineering design and construction and military software updates that feature Swedish technology, giving them missile launching capability. Following these upgrades, the ships were reclassified as destroyers. In 2008, the Pakistan Navy had carried out a successful test of the Camcopter S-100, an unmanned aerial vehicle, from the flight deck of a Tariq-class destroyer. The Tariq-class destroyers are currently in process of phasing out from their services, and were all planned to be decommissioned by 2020. Negotiation and procurement Procurement of Type 21 frigates dates back to 1966 when the UK first made an offer to Pakistan to jointly build three Type 21 frigates. The Ayub administration rejected the proposal as they wanted to allocate the funds to acquire s from France. Since 1966, the Pakistan Navy had wanted to acquire Type 21 frigates from the UK, submitting several proposals to the Government of Pakistan for acquiring the Type 21 frigates in 1970s. In 1987–88, Admiral Tariq Kamal Khan entered into negotiations with the Royal Navy and began lobbying the Zia administration for releasing the funds to acquire the Type 21 frigates in 1988. Despite the initial efforts with the Royal Navy, the Pakistan Navy leased four and four from the United States Navy in 1988; the selection was based on technological evaluation and Pakistani military specifications. The lease was set for five years with an option of renewing or purchasing the lease afterwards based on the mutual understanding between two nations. After the enforcement of the military embargo by the United States Congress in 1994, the lease was not renewed, therefore, the eight warships had to be returned to the United States Navy in Singapore, resulting Pakistan's sea borders vulnerable to foreign activities. During this time, Admiral Saeed Mohammad Khan used his personal relations with the