United States Army has a plan to deploy THAAD air defense missile systems in South Korea 2905141.

The U.S. has conducted a site survey in South Korea for possible locations for a Terminal High-Altitude Area Defense battery, or THAAD, but no final decisions have been made to deploy the system, the officials said.

The system is designed to intercept short, medium and intermediate missiles. Last year, in the face of provocations from North Korea, the U.S. deployed one such system to Guam to protect U.S. bases there.

Deploying a THAAD system to South Korea could represent an important incentive to encourage Seoul to cooperate more fully with the U.S. and Japan in a planned regional missile defense system.

South Korean officials have long indicated they don't want to participate in a U.S.-Japanese missile defense system, preferring instead to develop their own defenses. South Korean official reiterated that position on Tuesday.

The U.S. could deploy its own THAAD system to South Korea temporarily, and then, in time, replace it with a system purchased by Seoul, a defense official said. Or it could allow South Korea to purchase its own, and jump ahead in the queue for the system, the official said.

The U.S. plans to purchase seven THAAD systems, but only three so far are operational and competition among U.S. policy makers over where to deploy them is intense. Some policy makers want to send one of the systems to South Korea, others want one in the Middle East to defend against the threat of an Iranian attack, and yet others want to keep the two in reserve in case a major crisis breaks out.

Terminal High Altitude Area Defense (THAAD), formerly Theater High Altitude Area Defense, is a United States Army anti-ballistic missile system designed to shoot down short, medium, and intermediate ballistic missiles.

The THAAD (theatre high-altitude area defence) missile system is an easily transportable defensive weapon system to protect against hostile incoming threats such as tactical and theatre ballistic missiles at ranges of 200km and at altitudes up to 150km.