North Korea's military has raised an alert for its artillery units on the west coast in readiness for a planned live-fire drill by the South, a government source said today.
"We understand that there's been an upgrade in alert at artillery units," he said.
South Korean marines are expected to stage live-fire drills off Yeonpyeong island, hit by a North Korean bombardment last month, some time before nightfall on Tuesday.
North Korea has threatened another military attack if the live-fire drill goes ahead.
Meanwhile, a US envoy on an unofficial visit to North Korea yesterday warned that the situation on the peninsula is a “tinderbox.”
Mr Richardson, on a private mission to cool tensions, urged North Korea to show restraint and to let the rival South conduct exercises.
"There's enormous potential for miscalculation," he said "I'm urging (on the North) extreme restraint ... Let's cool things down."
Analysts were sceptical the North would carry out the threat it issued on Friday, which rattled financial markets and brought a vow by the South to retaliate against any attack by Pyongyang.
China, the North's main backer, urged both nations to refrain from acts that would inflame an already "extremely precarious" situation.
"The serious tension on the peninsula must not be allowed to escalate," Chinese Vice Foreign Minister Zhang Zhijun said today. "China is firmly against any behaviour that may result in the situation deteriorating or damaging regional stability."
Yeonpyeong is a usually sleepy place. But the island is also only a short distance from the Northern Line Limit (NLL) - the sea border declared at the end of the 1950-53 Korean War but still disputed by the North.
Many of the 1,600 residents, who live alongside 1,000 military personnel, are uneasy about the prospect of a new barrage and have chosen to leave for the mainland for a while.
Agencies