North And South Korea In Sea Border Clash
Peter Sharp, Asia correspondent
North and South Korea have exchanged fire near a disputed sea border off the west coast of the peninsula.
To view this content you need Flash and Javascript enabled in your browser. Please download Flash from the Adobe download website.
North Korean artillery fired around 30 rounds into the sea and the South responded with 100 shots from an island near the sea border.
There were no injuries and no naval vessels were said to have been involved.
A South Korean spokesman told the AFP news agency: "When the north fired, some 20 to 30 columns of water shot up into the sky."
The western coastal waters have been the scene of bloody naval exchanges in the past.
In November, a North Korean sailor was killed and a South Korean vessel badly shot up when both sides clashed in the disputed waters.
Sea borders are disputed
The latest incident came two days after North Korea declared two "no sail" zones in the area, leading to fears that the Pyongyang regime was preparing to test-fire another short-range missile in the area.
Last month, the communist North warned South Korean shipping to avoid the coastal area, saying its artillery would stage "live fire" exercises in response to "reckless military provocations" from the South.
"North Korea will likely continue such low intensity military provocations like this in the next few months," said Baek Seung Joo, of the Korea Institute for Defence Analyses.
"But it is unlikely to take things to the extreme as it in general wants to maintain economic cooperation with South Korea. And its ships are out-gunned by the South."
The sea border was drawn up by the United Nations Command at the end of the Korea War in 1953 and has long been a source of tension between the two countries.
The (disputed) sea line between North and South Korea.
North Korea and South Korea have exchanged fire near the disputed sea-border between the countries. There are no reports of casualties.

North Korea fired approximately thirty artillery shells into the water on their side of the border, near South Korea's Baengnyeong Island at 0900 local time (0000 UTC). The South retaliated with around 100 shots. 

According to the North, it took place as part of an annual drill. The Korean Central News Agency said that the exercise "will go on in the same waters in the future".

South Korea maintains that it responded by firing at the North's shells. Later reports from the South said that North Korea fired more shells in the general direction of the disputed border some hours after the initial exchange.

This latest incident comes after North Korea declared a 'no-sail' zone off its coastal waters yesterday.  It is not the first skirmish around the Military Demarcation Line – the most recent was in November 2009, when a North Korean vessel took "considerable damage" after allegedly crossing the border.