ISLAMABAD (APP) - Four Pakistan Army Mi-17 helicopters were returned to the Pakistan Army by the United States on Wednesday after the United States funded maintenance overhauls. The overhaul programme provides critical support to the Pakistan Army by expediting maintenance and returning urgently-needed aircraft to flight operations, a statement from the US embassy said. The helicopters were handed over to the Pakistan Army here at the Chaklala Air Base. The US has funded maintenance overhauls for 24 Pakistan Army Mi-17s, twelve of which were completed and returned to Pakistan last year. The remaining eight helicopters are scheduled for delivery later this year. The US is also coordinating with the Pakistan Army to fund overhauls for another 10 Mi-17s, and has recently delivered two Bell 412 helicopters to the Pakistan Army. Another 13 AH-1F Cobras have been procured for use as spare parts to further enhance operations of Pakistan Army Aviation. Since 2001, the United States has provided more than $12 billion to Pakistan in security assistance, training and equipment, which also includes $8.1 billion in Coalition Support Fund (CSF) reimbursements. Other security assistance delivered to Pakistan included: three F-16 Block 52 fighter aircraft for Pakistan Air Force; an additional 14 F-16 fighter aircraft delivered to PAF in 2008; five fast patrol boats to the Maritime Security Agency; two P-3C Orion maritime patrol aircraft delivered to the Pakistan Navy. The assistance also included 115 M109A5 Howitzer self-propelled field artillery cannons to the Pakistan Army; more than 450 vehicles for Pakistans Frontier Corps; and hundreds of night vision goggles, day and night scopes, radios, and thousands of protective vests and first-aid items for Pakistans security forces.