SEOUL/TOKYO (Reuters) - The United States, Japan and South Korea said in a joint statement they discussed the regularisation of missile defence and anti-submarine exercises to deter and respond to North Korea's nuclear and missile threats.

The announcement was made at the 13th Defence Trilateral Talks held on Friday in Washington D.C. to exchange assessments of the security environment on the Korean Peninsula and broader region, as well as to consult on concrete ways to deepen trilateral security cooperation, the joint statement said.

The representatives from the three countries "urged the DPRK to stop all destabilising activities immediately" and "reaffirmed that a DPRK nuclear test, if conducted, would be met with a strong and resolute response from the international community," the statement said, using North Korea's official name.

It follows North Korea's announcement on Friday that it had tested a new solid-fuel intercontinental ballistic missile (ICBM), a development set to "radically promote" its forces, which experts said would facilitate missile launches with little warning.

(Reporting by Jihoon Lee in Seoul, Mariko Katsumura in Tokyo; Editing by Diane Craft)