The defense chiefs of South Korea, the United States and Japan held talks on the phone and pledged close cooperation to counter missile threats from North Korea.

According to Seoul's defense ministry, Minister Suh Wook spoke on the phone with his American and Japanese counterparts, Lloyd Austin and Nobuo Kishi Thursday morning.

In the talks, Minister Suh said that the North's recent missile tests, including the launch of an intermediate-range ballistic missile, pose a "direct and serious threat" to South Korea. He added that they are a destabilizing act and a challenge to UN Security Council resolutions.

Minister Suh also said South Korea plans to further enhance its own defense capabilities and bolster its solid alliance with the U.S. in response to Pyongyang's nuclear and missile threats.

The defense chiefs also agreed to narrow down a schedule to meet face to face and to continue efforts to achieve the goal of denuclearizing the peninsula.