The military leaders of South Korea and the U.S. discussed ways to enhance interoperability between their countries’ ballistic missile defense systems and their capabilities to counter North Korea’ evolving security threats, Seoul’s Joint Chiefs of Staff said Friday.

South Korea’s JCS Chairman Choi Yun-hee and his U.S. counterpart Martin Dempsey held a meeting in Seoul, during which the two touched on an array of bilateral and regional security issues including the preparations for the conditions-based transition of wartime operation al control.

“We had very important and productive discussions today with your military leaders about the progress we have made on certain issues, like the command and control, an integrated air and missile defense and (military) exercises, in all of which we have made great progress over these past few years,” Dempsey said after his meeting with Choi.

The visit by the top U.S. military officer came as controversy rages over Washington’s possible deployment of an advanced missile defense asset, called Terminal High-Altitude Area Defense, to the Korean Peninsula.

Apparently to avoid further escalating the controversy, Seoul officials stressed that neither Choi nor Dempsey mentioned THAAD during their one-hour meeting.

The two governments have yet to begin any official consultations over the THAAD deployment, even though the U.S. military has already conducted a site survey to find potential locations for it in Korea.

Dempsey’s mention of the “progress” on an integrated air missile defense system sparked speculation that the U.S. might be pursuing an integration of its MD system and Seoul’s independent program, called Korea Air and Missile Defense.

But Seoul’s JCS officials dismissed the speculation, arguing that Dempsey just touched on the progress in the ongoing efforts to improve interoperability in the allies’ separate missile defense programs.

Seoul and Washington have been trying to link the South’s Air and Missile Defense-Cell and the U.S. Forces Korea’s Theater Missile Defense-Cell. The AMD-Cell and TMO-Cell are the interception control centers that the allies have sought to connect to enhance the sharing of their intelligence on hostile missiles.

“The discussions (between Choi and Dempsey) focused on how to maximize interoperability in the operations of their respective defense systems including Seoul’s KAMD and the ‘Kill Chain’ (preemptive strike) system,” a JCS official told reporters, declining to be named.

As the THAAD issue has been intensely debated here, observers say that the allies might soon begin their consultations over the issue. U.S. Defense Secretary Ashton Carter is set to travel to Seoul next month and may discuss the issue with Seoul officials, they presumed.

The THAAD issue has been a hot-button issue as China has repeatedly expressed its disapproval to its deployment in Korea, arguing that it would undermine China’s security interests. Seoul has been cautious, to avoid straining ties with Beijing, which is its largest trading partner.

On Thursday, China’s Defense Ministry spokesperson Geng Yansheng reiterated Beijing’s concerns over THAAD.

“Our stance on the deployment of the missile defense system in the Asia-Pacific region is clear and consistent. We think that to deploy the missile defense system by some countries in the Asia-Pacific region is neither conducive to the strategic stability and mutual trust, nor to regional peace and stability,” he said.

The THAAD is a core element of the U.S.’ multilayered missile defense program. It is designed to intercept short-, medium- and intermediate-range ballistic missiles at altitudes of 40 to 150 km during the final phase of their flight, after detecting them with a radar that has a maximum range of about 1,800 km.

By Song Sang-ho (sshluck@heraldcorp.com)