SEOUL, South Korea - North Korea fired more artillery near its disputed western sea border with South Korea on Thursday, a day after it lobbed dozens of shells during military exercises that prompted the South to respond with warning shots.
The shells fired early Thursday are believed to have landed in the North's waters, an official at Seoul's Joint Chiefs of Staff said. The official, speaking on condition of anonymity citing department policy, said South Korea did not respond but was closely watching the North's manoeuvrs.
The poorly marked sea border -- drawn by the American-led U.N. Command at the end of the Korean War -- is a constant source of tension between the two Koreas. Their navies fought a skirmish in November that left one North Korean sailor dead and three others wounded, and engaged in bloodier battles in the area in 1999 and 2002.
It was the first exchange of fire between the two Koreas since November and could be an attempt by North Korea to raise tensions to emphasize that the peninsula remains a war zone and aid its push for a treaty formally ending the 1950-53 Korean War.
That conflict ended in a truce, not a treaty, leaving the peninsula technically at war.
South Korea and the United States have insisted that North Korea return to nuclear disarmament talks before any treaty can be concluded.
On Wednesday morning, North Korea fired about 30 artillery rounds into the sea from its western coast, and South Korea quickly responded with 100 warning shots from a nearby marine base, Seoul's Defence Ministry and Joint Chiefs of Staff said.
The North said its moves were part of an annual drill and that they would continue. It has designated two no-sail zones in the area, including some South Korean-held waters, through March 29. No casualties or damage were reported.
In Washington, State Department spokesman P.J. Crowley criticized the North on Wednesday for raising tension, saying the firing were "provocative actions and, as such, are not helpful."
China called for restraint, Foreign Ministry spokesman Ma Zhaoxu told reporters.
North Korea argues that it was compelled to develop nuclear weapons to cope with a military threat from the U.S.
North Korea is said to believe a peace treaty with the U.S. would provide security and status, help ensure the survival of its government and give it a stronger hand against rival South Korea. A treaty could also raise the question of whether the U.S. needs to maintain about 28,500 troops in the South -- a legacy of the war.
On South Korea's Baekryung island near the disputed waters, local fishing boats were forbidden to go out into the waters, though at least two Chinese fishing vessels could be seen operating.
Kim Wae-soon, a shop owner on the island, said the tensions didn't scare her.
"I do not feel insecure," she said. "North Korea does this when it gets bored, so I do not even care nowadays. Every time these incidents happen, don't you think North Koreans do so because they need something?"
Separately, North Korea announced Thursday it is holding an American man who crossed into its territory from China. It did not identify him. Late last month, North Korea said that it had detained another U.S. citizen for illegally entering the country. He is widely believed to be Robert Park, an American missionary.
