The U.S. Congressional Research Service reports that Pakistan has signed $5.4 billion in Foreign Military Sales contracts from fiscal 2001 to fiscal 2014.

Procurement of F-16 aircraft and related equipment account for more than half of the sum.

"Major U.S. arms sales and grants to Pakistan since 2001 have included numerous items useful for counter-terrorism and counter-insurgency operations, along with a number of "big ticket" platforms more suited to conventional warfare," the service said in its report. "In dollar value terms, the bulk of purchases have been made with Pakistani national funds, although U.S. grants have eclipsed these in recent years."

CSR said Congress has appropriated about $3.6 billion in Foreign Military Financing, or FMF, for Pakistan since 2001 and more than two-thirds of that has been disbursed. Pakistan also has been given U.S. defense supplies as Excess Defense Articles and training was provided for the use of those articles.

Excess Defense Articles are systems no longer needed by the U.S. Armed Forces. They are offered at a reduced cost or no-cost basis to eligible foreign recipients on an "as is, where is" basis. Refurbishment, however, is the financial responsibility of recipients.

Major post-2001 defense supplies procured, or being procured by Pakistan through the Foreign Military Sales program, are eight P-3C Orion maritime patrol aircraft and their refurbishment (four were delivered but three of them were subsequently destroyed in a 2011 terrorist attack); at least 5,750 military radio sets; 2,007 TOW anti-armor missiles; six AN/TPS-77 surveillance radars; six C-130E Hercules transport aircraft and their refurbishment; a Perry-class missile frigate; 20 refurbished AH-1F Cobra attack helicopters, of which 12 have been delivered; and 15 Scan Eagle reconnaissance unmanned aerial vehicles.

Items procured with a mix of Pakistani national funds and U.S. FMF include, 45 Mid-Life Update kits for F-16A/B combat aircraft AND 115 M-109 self-propelled howitzers, CSR said.

"Notable items paid or to be paid for entirely with Pakistani national funds include 18 new F-16C/D Block 52 Fighting Falcon combat aircraft (valued at $1.43 billion); F-16 armaments including 500 AMRAAM air-to-air missiles; 1,450 2,000-pound bombs; 500 JDAM Tail Kits for gravity bombs; and 1,600 Enhanced Paveway laser-guided kits for gravity bombs; 100 Harpoon anti-ship missiles; 500 Sidewinder air-to-air missiles; and seven Phalanx Close-In Weapons System naval guns."

A new $952 million FMS deal to provide Pakistan for 15 AH-1Z Viper attack helicopters, missiles and other items was approved by the State Department last month.