The governments in Pyongyang and Seoul have accused each other of responsibility for Saturday's clash in their disputed maritime border zone.

The official North Korean news agency KCNA quotes a military source as saying: "The South Korean army committed such a grave provocation as firing bullets and shells at patrol boats of the navy of the Korean People's Army on routine coastal guard duty in the West Sea of Korea today".

The incident was a premeditated military provocation

North Korean military official

"Warships of the South Korean navy fired hundreds of bullets and shells at our patrol boats when they moved out to stop those warships which had intruded deep into our territorial waters, southwest of Yonphyong Islet, together with at least 10 fishing vessels," the English-language statement says.

'Self Defence'

"In retaliation against this, DPRK [North Korean] warships were compelled to take a self-defensive step. As a result, there was an exchange of fire between the two sides, causing losses.

"The incident was a premeditated military provocation on the part of the South Korean military from A to Z.

They can never flee from the responsibility for the armed provocations

North Korean military official

"Recently, the South Korean army infiltrated warships and fishing boats deep into the territorial waters of the North side almost everyday and they pretended to retreat from there when naval patrol boats of the North sailed there, straining the situation.

"The South Korean military authorities sought to invent any shocking incident in the West sea, thus aggravating the inter-Korean relations that have been in the process of detente.

"They can never flee from the responsibility for the armed provocations. They should stop acting rashly, mindful of the grave consequences to be entailed by such provocations," the North Korean statement concludes.

The provocation by North Korean patrol boats is a flagrant violation of the cease fire agreement which we will never overlook

South Korean leader Kim Dae-jung

"Flagrant violation"

Meanwhile, South Korea's Seoul National Security Council pledged to take "strong military steps" against North Korea after President Kim Dae-jung called an emergency session in the wake of the incident.

"The provocation by North Korean patrol boats is a flagrant violation of the cease fire agreement which we will never overlook, " Kim said.

"Military authorities should take steps to make our forces even better prepared against similar aggressions," the president said.

Defence Minister Kim Dong-shin issued a statement demanding an apology for the incident and calling for the "perpetrators of such dastardly preemptive attacks" to be punished.

The exchange of fire is feared to rapidly chill inter-Korean relations

Yonhap news agency

The statement also called for a pledge that there would be no recurrence of such incidents, South Korea's Yonhap news agency reports.

A Defence Ministry statement says: "Two North Korean patrol boats and fishing boats violated the Northern Limit Line 0954, and entered 17 miles and 7 miles into South Korean waters. Hence, our patrol boats rushed to the scene and gave warning through loudspeakers several times, urging them to return to their waters. But the North Korean boats neglected the warnings and suddenly made a preemptive attack."

Yonhap adds: "The exchange of fire is feared to rapidly chill inter-Korean relations that have sporadically moved towards reconciliation and cooperation following the historic inter-Korean summit in June 2000".

BBC Monitoring, based in Caversham in southern England, selects and translates information from radio, television, press, news agencies and the Internet from 150 countries in more than 70 languages.