The nominee to be South Korea's new spy chief said Monday that all options should be on the table when dealing with threats posed by North Korea's nuclear and missile programs.
  

Lee Byung-ho made the comment when asked by a lawmaker about an advanced U.S. missile-defense system that Washington hopes to deploy to South Korea.
  

Lee said a Terminal High Altitude Area Defense battery is an issue of South Korea's sovereignty.
  

His comments came as South Korea is struggling to walk a diplomatic tight rope between the U.S., Seoul's key ally, and China, Seoul's largest trading partner, over the sensitive security issue.
  

THAAD is designed to shoot down ballistic missiles in their terminal stage using a hit-to-kill program.
  

Washington says the THAAD battery is a purely defensive system designed only to counter ballistic missile threats from North Korea.
  

Still, China has repeatedly expressed its opposition to the possible deployment of a THAAD battery in South Korea as the radar system can monitor military facilities in China.
  

"It would be appreciated if Seoul takes into account China's concerns and worries," Chinese Assistant Minister of Foreign Affairs Liu Jianchao said after a meeting with his South Korean counterpart Lee Kyung-soo in Seoul.
  

Liu, who arrived in Seoul on Sunday for a four-day visit, expressed China's hope that South Korea and the U.S. make the "appropriate" decision on the issue.
  

Liu's visit to Seoul coincided with a trip by U.S. Assistant Secretary of State Daniel Russel.
  

Russel arrived in Seoul on Monday for a two-day visit, during which he is likely to discuss the U.S. missile defense system and issues of mutual interest with his Korean counterpart.
  

South Korea has said it made no decision on whether to allow the U.S. to deploy an advanced missile defense battery to South Korea in what could be the latest attempt to maintain strategic ambiguity over an issue that may hurt its ties with either the U.S. or China.
  

South Korea has long been under security threats posed by North Korea's missile and nuclear weapons programs. The country, including its capital city of Seoul with more than 10 million people, is within striking distance of North Korea's missiles.
  

"The threats posed by North Korea are considerably substantial and we need to brace for them," Lee said at the hearing.
  

South Korean officials have said a THAAD battery, if deployed by U.S. troops in South Korea, could be helpful in the country's security and defense. About 28,500 U.S. troops are stationed in South Korea as a deterrence against North Korea.
  

Lee also said South Korean activists and North Korean defectors should continue their "efforts to spread the truth to North Korea," referring to leaflets critical of North Korean leader Kim Jong-un.
  

However, he mentioned that the South Korean government should take steps in the leaflet campaign in case public safety is jeopardized as well, though he did not elaborate.
  

Propaganda leaflets have long been a constant source of tension between the two rival Koreas. Tension flared up in October when the two Koreas exchanged machine gun fire across the border after the North apparently tried to shoot down balloons carrying anti-Pyongyang leaflets.
  

North Korea, which bristles at any outside criticism of its leader, has since ratcheted up rhetoric against South Korea over the anti-Pyongyang leaflets.
  

Lee also vowed not to engage in any illegal activities as he promised to reform the National Intelligence Service, South Korea's top spy agency whose image was sullied by a series of scandals, including election meddling, in recent decades.
  

Lee said he will make a clear break from the past, noting that any political intervention by the agency will "ruin the NIS."
  

Last month, the Seoul High Court sentenced Won Sei-hoon, who headed the NIS from 2009 to 2013, to three years in prison for intervening in the 2012 presidential election.
  

The parliamentary confirmation hearing is widely seen as a formality because Lee's formal appointment as the spy chief does not require approval from the National Assembly. (Yonhap)