South Korea-US begin talks on THAAD missile system deployment

South Korea on Sunday announced the start of official negotiations with the US on possible deployment of an advanced US missile defence system after North Korea's nuclear test and long-range rocket launch.

The start of talks about deployment of Terminal High Altitude Area Defence (THAAD) system to US forces in Korea (USFK) came just hours after Pyongyang announced the successful launch of its Kwangmyongsong-4 Earth observation satellite into orbit in defiance of international warnings, Xinhua reported.

A rocket carrying the satellite was seen by Seoul and Washington as a long-range ballistic missile.

UN Security Council resolutions ban Pyongyang from testing a rocket by use of ballistic missile technology. On January 6, North Korea tested what it claimed was its first H-bomb.

Yoo Jeh-Seung, South Korea's deputy defence minister for policy, said Seoul and Washington had shared a view that North Korea's recent nuclear test and long-range rocket launch are a serious threat to peace and stability in South Korea and the entire Asia-Pacific region.

To respond to the mounting North Korea threats, South Korea and the US decided to kick off negotiations on the THAAD deployment to enhance a joint missile defence posture between the two allies, Yoo said.

The decision was made after USFK commander Curtis Scaparrotti requested it, Yoo said, noting that the talks are aimed at jointly seeking possible THAAD deployment and its operational capability at the earliest.

Repeated tests by Pyongyang of its nuclear devices and long-range rockets are believed to have advanced its capability of miniaturising a nuclear warhead small enough to fit on a long-range missile that can strike the US mainland.

Pyongyang had conducted nuclear tests and long-range rocket launches almost simultaneously. About a month after the fourth nuclear test, the Kwangmyongsong rocket lifted off from North Korea's main Tonchang-ri launch station on the west coast.

Two months before the third nuclear detonation, North Korea launched a three-stage Unha-3 rocket into space for the purpose of what it claimed was to deliver an observation satellite.

South Korea and the US will form a joint working group that would first review an appropriate site for the THAAD deployment.

If the THAAD is deployed in the northeastern coastal region of South Korea, it can intercept ballistic missiles launched from DPRK submarines, a South Korean defence ministry official said.

North Korea reportedly test-fired its submarine-launched ballistic missiles (SLBM) three times in 2015.

The SLBM is seen by some as the most serious threat as a submarine-carried ballistic missile is much harder to detect in advance.

The THAAD is an advanced US missile defence system designed to shoot down ballistic missiles at an altitude of 40-150 km. A THAAD battery is composed of six mobile launchers, 48 missiles and airborne radar and fire control system.

The US had expressed its willingness to deploy one or more batteries in South Korea.

One THAAD battery, valued at about 1.5 trillion won ($1.3 billion), is capable of covering two thirds of South Korea, according to Seoul's defence ministry.

The South Korean military has no plans to directly purchase the US missile defence system, and possible deployment will be made to US troops stationed in South Korea, a legacy of the 1950-53 Korean War.

If deployed, Seoul would bear the costs for the site and infrastructure, while Washington would cover costs for the deployment and maintenance.

The THAAD will be operated against North Korea alone, according to Seoul's defence ministry.

The ministry believes that it can shoot down an estimated 2,000 North Korean ballistic missiles, including Scud, Rodong and Musudan.