The U.S. Defense Department said Thursday no formal consultations have taken place with South Korea about the possible deployment of a THAAD missile defense battery to the country, rejecting a Lockheed Martin official's claim that discussions are already under way.

"We have made no final decision regarding the deployment of a U.S. THAAD unit to the Republic of Korea, nor have we had any formal consultations with the ROK government on this issue," Cmdr. Bill Urban, a U.S. Defense Department spokesman, said in comments to Yonhap News Agency.

Earlier in the day, Mike Trotsky, vice president of air and missile defense at Lockheed Martin, claimed during a National Press Club news conference that the two countries have already been in "formal and informal discussions" on the sensitive issue.

"The THAAD system is the subject of a policy discussion between the United States and the Republic of South Korea. Those policy discussions are ongoing now," Trotsky told reporters.

"As those discussions evolve, if there is an interest on the part of both countries to do something with THAAD, then of course, Lockheed Martin will enthusiastically support it," he said. He also said the discussions are at "a very beginning state."

Trotsky's claim came ahead of U.S. Defense Secretary Ash Carter's trip to South Korea for the annual defense ministers' talks with Seoul's Defense Minister Han Min-koo, raising speculation that it might be a topic for the upcoming talks.

The Pentagon spokesman declined comment on whether the issue could be on the agenda.

"We are not going to be able to provide any information on what Secretary Carter is going to talk to his South Korean counterpart about until after the meetings occur," he said.

THAAD, which stands for Terminal High Altitude Area Defense, is considered one of the most advanced missile defense systems in the world, and is manufactured by Lockheed Martin.

The U.S. wants to deploy a THAAD unit to South Korea, where some 28,500 American troops are stationed, to better defend against ever-growing threats from North Korea's ballistic missile and nuclear programs.

But the issue has become one of the most sensitive for South Korea because China sees a THAAD deployment as a threat to their security interests and has increased pressure on Seoul to reject such a move.

Seoul and Washington have repeatedly claimed they have never held any formal consultations on the issue.

A South Korean government official also rejected Trotsky's claims, saying that there has been no discussion on the THAAD deployment under way between Seoul and Washington as the U.S. has not even made a request for holding such talks.

"If the U.S. makes such a request, we will, then, decide on the issue from the perspective of national interests," the official told Yonhap News Agency by phone.

Trotsky said the U.S. missile defense system is designed in a layered architecture consisting of sea-based Aegis weapon systems, THAAD systems, and Patriot systems to ensure that enemy attacks won't penetrate all those layers. Such a layered system is also necessary for South Korea, he said.

"So, having those layers makes it extremely difficult for the enemy to deploy any one technique that would defeat all three systems," he said. "In a country like Korea, it might make sense to have more than one layer, to have a multi-layer system that is comprised of THAAD and PAC-3 or Aegis weapons system and PAC-3."

The official also stressed that THAAD is a purely defensive system.

"It can't be used in an offensive way. The entire system, from the hardware to the software, must have an incoming ballistic missile to launch an interceptor," he said. "It's a defensive weapons system. It would have to be completely redesigned to operate as an offensive weapons system." (Yonhap)