SEOUL, Feb 7 (Reuters) - South Korea said on Sunday it and the United States would begin discussion on deploying an advanced missile-defence system to South Korea to counter the growing threat of North Korea's weapons capabilities. U.S. military officials have said the sophisticated system called Terminal High Altitude Area Defence (THAAD) was needed in South Korea, which faces the threat of an increasingly advanced North Korean missile programme. "If THAAD is deployed to the Korean peninsula, it will be only operated against North Korea," Yoo Jeh-seung, a senior official at the South Korean defence ministry said in a joint news conference with Thomas S. Vandal, commander of the Eighth U.S. Army based in South Korea. North Korea launched a long-range rocket earlier on Sunday carrying what it has called a satellite. South Korea, other neighbours and Washington denounced the launch as a missile test.