North Korea says planned naval exercises by the United States and South Korea are a threat to its sovereignty and the region.
A member of Pyongyang's delegation to an Asia-Pacific security meeting being held in Vietnam says such threats will be met with what he calls a physical response.
The US and South Korea say the exercises, beginning on Sunday, should deter North Korea from further attacks after the torpedoing of a South Korean warship in March.
North Korea denies involvement in the sinking.
