“A North Korean propaganda website has warned of strikes against Southern islands and advised residents to leave.
The Uriminzokkiri website … mentioned targets including Yeonpyeong island, which was attacked by Northern forces in 2010.
Pyongyang has made a series of threats since its last nuclear test in February prompted the UN to tighten sanctions.
The US said on Friday it would refocus missile defences to its west coast to counter the North’s threats.
Defence Secretary Chuck Hagel said 14 more batteries would be placed in Alaska by 2017, adding to 30 already in place.
The Uriminzokkiri website stated: “Even an accidental spark by the belligerents in their war games can grow into a fire.
“And the damage for those living along the border and on the five western islands will be great.”
The threats came shortly after South Korean Prime Minister Chung Hong-won visited Yeonpyeong.