WASHINGTON -- The defense chiefs of South Korea and the United States reaffirmed Monday that their alliance is the "linchpin" of regional peace and security.

The acknowledgment from South Korean Defense Minister Song Young-moo and US Defense Secretary Jim Mattis comes as tensions have heightened over North Korea's nuclear and ballistic missile programs.

The two met on the sidelines of a regional defense ministerial meeting in the Philippines earlier in the day.

"Secretary Mattis and Minister Song reaffirmed the US-ROK alliance is the linchpin of peace and security in the Asia-Pacific region," Pentagon chief spokesperson Dana White said in a statement. ROK is the acronym of South Korea's official name, the Republic of Korea.

They agreed to continue discussions in Seoul on Saturday when they meet for annual bilateral security talks.

Mattis also met with his Japanese counterpart, Itsunori Onodera, and reaffirmed that the two countries' alliance is the "cornerstone" of regional peace, prosperity and freedom, White said in a separate statement.

They condemned North Korea's provocations and nuclear and ballistic missile programs "in the strongest terms" and vowed to continue deepening bilateral and trilateral cooperation with South Korea to "deter and respond to threats posed by the (North Korean) Kim Jong-un regime."

In trilateral talks involving all three defense chiefs, they called on North Korea to abandon its weapons programs in a complete, verifiable and irreversible manner.

The ministers also agreed to work closer together to improve information sharing on North Korea's nuclear and missile threats and to strengthen their responses to those threats.

"The three Ministers pledged to actively cooperate to support diplomatic-led efforts to resolve North Korean nuclear issue through maximum pressure on North Korea," a joint press statement said. "The three Ministers committed to continue efforts to backstop the international community's efforts to curb North Korea's weapons of mass destruction programs and their means of delivery."

Mattis also highlighted the urgency of the North Korea issue during a meeting with his counterparts from the 10 members of the Association of Southeast Asian Nations.

"Secretary Mattis emphasized the need for continued cooperation in the international community to apply greater diplomatic and economic pressure on North Korea to fully implement all UN Security Council resolutions," White said. (Yonhap)