 With US assistance, in the largest covert operation in history, Pakistan armed and supplied anti-Soviet fighters in Afghanistan.In the 1980s, Pakistan agreed to pay $658 million for 28 F-16 fighter jets from the United States; however, the US congress froze the deal, citing objections to Pakistan's nuclear ambitions.Under the terms of the American cancellation, the US kept both the money and the planes, leading to angry claims of theft by Pakistanis.