The US THAAD missile defense system being installed in South Korea is "critical" to defending the Asian ally from North Korean threats, the White House said Wednesday.

"We're very troubled by the launch of missiles that have occurred from North Korea. I think that's why the THAAD missile system that we've started to deploy into South Korea is so important," White House press secretary Sean Spicer said at a regular briefing.

"We're continuing to work with the government of South Korea to make sure they have the defenses necessary to protect themselves.
 

The deployment of the THAAD system is critical to their protection as witnessed by this weekend's ballistic missile tests," he said.

China angrily reacted to the arrival in South Korea earlier this week of the first elements of a Terminal High Altitude Area Defense battery that the US and the South agreed to install to bolster defenses against growing missile threats from North Korea.

Beijing has long opposed the deployment, claiming the system, especially its radar, can be used against the country. In recent months, China has taken a number of unreasonable steps against South Korean businesses in apparent retaliation for Seoul's hosting of the system.

Earlier Wednesday, Chinese Foreign Minister Wang Yi strongly denounced the deployment, warning that it will make South Korea "less secure" and the neighboring nation would end up "hurting themselves."

State Department acting spokesman Mark Toner said the Chinese concerns are unwarranted.

"The reason we're undertaking the deployment of THAAD with the consent of the Republic of Korea is out of our concern that North Korea's nuclear program poses, for the peninsula. It is clearly not aimed at, in any way, shape or form, China," he said. "It is a defensive system. We've made that very clear, and we'll continue to make that clear with China going forward." (Yonhap)