SEOUL: North Korea may test-launch an intercontinental ballistic missile (ICBM) this month, a senior South Korean official said on Friday before discussions with U.S. officials on responses to Pyongyang's nuclear weapons threats.

Kim Tae-hyo, South Korea's deputy national security adviser, declined to elaborate on the basis of his comments but said North Korea's ballistic missiles are the focus of Washington's "extended deterrence" strategy.

"Extended deterrence is about finding a way to put down (a nuclear attack) early and decisively, and now, in December, I believe there's a possibility of an ICBM launch by North Korea," Kim told reporters as he arrived in Washington.

North Korea's ballistic missiles are a nuclear threat regardless of their range because they can carry a nuclear warhead, Kim added.

North Korea has developed and tested a range of ballistic missiles that can reach targets in South Korea, Japan, and the mainland United States.

Under conservative President Yoon Suk Yeol, South Korea has stepped up efforts to bolster its defences against North Korea, focused on the use of U.S. strategic military assets, including nuclear weapons, in the event of a war.

Kim is in Washington for the second round of the Nuclear Consultative Group (NCG) talks on Friday, high-level discussions between the leaders of South Korea and the United States aimed at coordinating the extended deterrence strategy.

Kim also said that a proposed real-time data sharing programme on North Korean missiles among South Korea, Japan and the United States are "in the completion stage" and that there would soon be an formal announcement.

North Korea tested a long-range ballistic missile in July, which analysts said was a successful launch of a solid-fuel ICBM that flew on a lofted trajectory and reached an altitude of 6,648 kilometres (4131 miles) before dropping into the sea east of the Korean Peninsula.

In November, North Korea launched its first military reconnaissance satellite on a two-stage space launch vehicle, drawing condemnation from South Korea and the United States for using banned ballistic missile technology.