The plans to deploy the Terminal High-Altitude Area Defense system, or THAAD, within this year have angered not only North Korea, but also China and Russia, which see the system's powerful radars as a security threat. Washington and Seoul say the system is defensive and not meant to be a threat to Beijing or Moscow. Shoots down short and medium-range ballistic missiles in the terminal phase of their flight 
 
 Uses hit-to-kill technology - where kinetic energy destroys the incoming warhead 
 
 Has a range of 200km and can reach an altitude of 150km 
 
 US has previously deployed it in Guam and Hawaii as a measure against potential attacks from North Korea 
 
 What impact will S Korea's expanded missile defence system have? "Continued provocative actions by North Korea, to include yesterday's launch of multiple missiles, only confirm the prudence of our alliance decision last year to deploy THAAD to South Korea," Adm. Harry Harris, head of the U.S. Pacific Command, said in the statement. Chinese foreign spokesman Geng Shuang said on Tuesday that China opposed the deployment and would "resolutely take necessary measures to defend our own security interests". China's condemnation of South Korea's plans to deploy THAAD has triggered protests against a South Korean retail giant, Lotte, which agreed to provide one of its golf courses in southern South Korea as the site of THAAD. While South Korea's media speculate that the THAAD deployment could be completed by as early as April, the ministry official couldn't confirm those reports. The official said that the plan was to have the system operational as soon as possible. On Monday, North Korea fired four ballistic missiles in an apparent protest against ongoing U.S.-South Korean military drills that it views as an invasion rehearsal. The missiles flew about 1,000 kilometers (620 miles) on average, three of them landing in waters that Japan claims as its exclusive economic zone, according to South Korean and Japanese officials. South Korea's Joint Chiefs of Staff said that the missiles fired by the North were believed to be "improved versions" of Scud missiles.
– US missile launchers and other equipment needed to set up a controversial missile defense system have arrived in South Korea, the US and South Korean militaries said Tuesday, a day after North Korea test-launched four ballistic missiles into the ocean near Japan. The plans to deploy the Terminal High-Altitude Area Defense system, or THAAD, within this year have angered not only North Korea, but also China and Russia, which see the system's powerful radars as a security threat, the AP reports. China firmly opposes the deployment and it responded quickly, saying it will take "necessary measures" to protect itself and warning that the US and South Korea should be prepared to bear the consequences. Washington and Seoul say the system is defensive and not meant to be a threat to Beijing or Moscow. The US military said in a statement that THAAD can intercept and destroy short and medium range ballistic missiles during the last part of their flights. "Continued provocative actions by North Korea, to include yesterday's launch of multiple missiles, only confirm the prudence of our alliance decision last year to deploy THAAD to South Korea," Adm. Harry Harris, head of the US Pacific Command, said in the statement. The BBC reports that there is also opposition within South Korea, with those living near missile sites fearing that the system itself could become a target.