South Korea plans to finalize the deal on buying four Global Hawks from Northrop Grumman in the first half of this year for better surveillance capability on North Korea, a senior acquisition official said Thursday.

Last year, Seoul received sales approval from the U.S. for the high-altitude, long-endurance unmanned aerial vehicles, which are sold only through the Foreign Military Sales program.

The state-run Defense Acquisition Program Administration in April 2013 sent a letter of request and received a letter of acceptance from the Pentagon on four RQ-4 Block 30s with an estimated budget set at about 900 billion won ($844.9 million).

“We will sign a deal on Global Hawks with the U.S. government in the first half of this year to better monitor North Korea and around the Korean Peninsula,” the senior DAPA official said on condition of anonymity, citing the ongoing procedure.

The procurement agency is currently consulting with the finance ministry to expand the initial budget, which was set at 480 billion won based on a cost estimate from several years ago, the official said.

If signed, South Korea plans deploy the advanced spy drones by 2018, he said.

Global Hawks operate at considerable stand-off distances and in any weather or light conditions, and can carry up to 1,360 kilograms of internal payload.

Northrop Grumman officials stressed the spy drone can well fit into the Korean Air and Missile Defense currently under development by providing surveillance and reconnaissance capabilities for early actions in time of conflict, calling it the “Eyes of Kill Chain.”

The Kill Chain defense system is designed to detect signs of impending missile attacks and launch pre-emptive attacks, while KAMD will intercept North Korean missiles that are already fired and are on route toward the target. (Yonhap)