South Korea has deployed the latest upgraded model of Apache helicopters, which are expected to enhance its overall combat capability, the country's defense procurement agency said Thursday.

According to the Defense Acquisition Procurement Administration, four AH-64E Guardians were delivered to Army units, which recently completed combat deployment. The four are the first to reach front-line South Korean combat units.

The agency signed a $1.6 billion contract with the U.S. in 2013 to buy 36 AH-64Es, an upgraded model of the AH-64D Longbow. It is to deliver all of the Apache helicopters to the Army by early next year.

The AH-64E is a heavily armed helicopter featuring more powerful, fuel-efficient engines and enhanced rotor blades. It has improved aircraft handling compared to older models with superior performance and agility at higher altitudes.

The attack choppers are also equipped with updated sensors that improve a crew's situational awareness and can strike a more diverse range of targets.

"We will deliver all helicopters and other support equipment as planned," DAPA said. "The Army plans to ensure operational capacity for the new choppers by training pilots and repair staff through live-fire drills and other real combat-like training programs."  (Yonhap)