North Korea's old subs still deadly

TOKYO - Experts say North Korea's submarine fleet is technologically backward, prone to sinking or running aground and all but useless outside its own coastal waters.

And yet many are asking: could it have been responsible for the explosion that sank a South Korean warship in March? And how could a sub have slipped through the defences of South Korea, which, with significant American backing, maintains a fleet far more sophisticated than its northern neighbour's?

Evidence collected so far indicates a torpedo hit the Cheonan, killing 46 sailors, and suspicion is growing that it was launched from a small North Korean submarine. That scenario would make it the most serious attack on the South Korean military since the peninsula's war ended in a truce in 1953.

"While the North Korean submarine force reflects dated technology by Western standards, North Korean submarines during wartime would present significant challenges, particularly in coastal areas," according to the Arlington, Virginia-based Global Security think-tank.

"North Korea has placed high priority on submarine construction programmes, which are ongoing despite its economic hardships."

North Korean subs are not state-of-the-art. Instead, they underscore impoverished North Korea's focus on "asymmetric" warfare - the use of stealthy, relatively low-cost weapons that many a ragtag fighting force have proved can open up big holes in conventional defences.

The "vast majority" operated by the North Korean Navy and intelligence agencies are capable of carrying torpedoes and sea mines, as are some of the intelligence agencies' semi-submersible infiltration landing craft, Joseph Bermudez, a North Korea military expert, said.

"If the sinking was caused by a torpedo, then I would say that this was a deliberate act of aggression," Bermudez added.

The idea that a North Korean submersible may have slid so close to the Cheonan undetected has been a wake-up call for the South, which has vowed to strengthen its defences against low-tech, asymmetric warfare. Seoul has now set up a task force to review and revamp its defences.

Many South Korean experts had previously thought that such subs were unable to launch effective attacks, and were of more use for simply crossing the border.

"It shows that both the South Korean and United States surveillance and reconnaissance missions either failed or were not in operation in the area where the incident took place," Tong Kim, a visiting professor at Korea University in Seoul, said.

- AP