Martin Navias

Live blog: Korea tension

19:03 GMT The US plans to consult with allies, including Chin,a to develop a "measured and unified" response to the artillery exchange, the US state department says.

"Everybody involved is stunned by North Korea's provocative actions," Mark Toner, a state department spokesman, said.

"We are working again within an established framework with our partners so we have a deliberate approach to this.