The defense chiefs of South Korea and the United States held talks on the margins of a security forum in Singapore on Saturday to discuss joint deterrence against North Korea's nuclear and missile threats, Seoul's defense ministry said.

Defense Minister Lee Jong-sup and his U.S. counterpart, Lloyd Austin, met on the margins of the annual Shangri-La Dialogue amid concerns about the possibility of Pyongyang conducting what would be its seventh nuclear test.

"Basically, we discussed various ways to increase the enforceability of extended deterrence," Lee told reporters after the talks without elaboration.

Extended deterrence refers to America's stated commitment to mobilizing a full range of its military capabilities, including nuclear options, to defend its ally.

Austin stressed Washington's determination to offer extended deterrence involving the whole range of its military capabilities, including nuclear, conventional and missile defense capabilities, according to Seoul's defense ministry.

Lee and Austin also reiterated the two countries' commitment to expanding the scope and scale of combined military exercises and training as agreed upon during last month's summit between President Yoon Suk-yeol and his U.S. counterpart, Joe Biden.

Lee used the talks to stress the importance of joint efforts to reactivate the two countries' Extended Deterrence Strategy and Consultation Group, hold tabletop exercises on the use of deterrence assets and deploy U.S. strategic military assets in a coordinated, timely manner, according to the ministry.

Lee and Austin strongly condemned the North's recent series of missile launches and its preparations for a nuclear test, calling them "provocative acts that seriously threaten peace and stability" on the peninsula and beyond.

Touching on trilateral cooperation among the South, the U.S. and Japan, Lee told reporters that there is a "difference" in depth between one involving Seoul and Washington and the one between Seoul and Tokyo.

Washington has been striving to bring its two Asian allies closer together for deeper security cooperation between them. Historical tensions stemming from Japan's 1910-45 colonization of the Korean Peninsula have gotten in the way.

Saturday's meeting marked the first face-to-face talks between Lee and Austin since Lee took office last month.

Later in the day, Lee and Austin joined their Japanese counterpart, Nobuo Kishi, for a trilateral session.

The three countries last held three-way face-to-face defense ministerial talks in November 2019. (Yonhap)