Nuclear response threat from Korea
North Korea says that joint US and South Korean military exercises to begin this weekend amount to a military provocation that will draw a "powerful" nuclear response from Pyongyang.
North Korea routinely threatens war when South Korea and the US hold joint exercises, which Pyongyang sees as a rehearsal for an attack on the North.
The latest threat comes amid increased tensions on the peninsula over the deadly sinking of a South Korean warship that Seoul and Washington blame on Pyongyang.
The allies' defence chiefs announced earlier in the week that they would stage the drills to send a clear message to North Korea to stop its "aggressive" behaviour.
Forty-six South Korean sailors were killed in the March sinking of the Cheonan in March.