... and warship blueprints from South

Approximately 40,000 files including 60 classified military documents were taken from the shipbuilding giant Daewoo Shipbuilding & Marine Engineering.

North Korean hackers have scored yet another win after stealing blueprints for South Korean warships and submarines while breaking into Daewoo Shipbuilding & Marine Engineering Co Ltd's database in April last year, a South Korean opposition lawmaker said on Tuesday.

Approximately 40,000 files including 60 classified military documents were taken from the shipbuilding giant, including technology for building the warships, weapons systems, blueprints and test data, according to Kyung Dae-soo of the main opposition Liberty Korea Party

"We are almost 100 percent certain that North Korean hackers were behind the hacking and stole the company's sensitive documents," Kyung told Reuters by telephone.

Long thought of as an unequal adversary that has lost its edge since the 1953 armistice and relies on amassed and aged artillery batteries, North Korea has used its resourcefulness to perfect and sharpen the asymmetrical capabilities needed to weather various storms and remain one step ahead of South Korean and U.S. war planners.

Among these resources is North Korea's alleged cyber-army, which South Korean experts estimate numbers nearly 6,800.

North Korea is often accused of waging cyber attacks on South Korean and international targets but Pyongyang has either ignored or denied accusations of hacking. However, the latest hack offers more proof that the North is effectively deploying its capabilities to frustrate its opponents.

Earlier this month, another South Korean lawmaker had said that North Korea's hackers stole a massive number of classified military documents totaling 253 gigabytes, including top-secret South Korea-U.S. wartime operational plans.

Daewoo Shipbuilding has built several South Korean warships, including an Aegis-class vessel and submarines. The blueprints are likely now in the hands of North Korea according to the lawmaker.

The hacking was discovered by a division under South Korea's Ministry of Defense in charge of investigating cases of cybercrime, said Kyung, who received a briefing on the investigation.

How sensitive and classified the seized documents were was not known as that was not disclosed by the investigative team, he added.

A spokeswoman for Daewoo Shipbuilding said she was unaware of the issue until early Tuesday and the company was in the process of confirming the details of Kyung's remarks.

The investigative team came to the conclusion that North Korea had hacked Daewoo Shipbuilding because the hacking method was very similar to other attacks that North Korea was thought to be behind, Kyung said.

British authorities said last week they believed Pyongyang was behind the "WannaCry" ransomware attack in May that disrupted businesses and government services worldwide, including the National Health Service in England.

The Korea-Europe Association, a pro-North Korea organization, has vociferously denied the accusation.

"The moves of the U.K. government to doggedly associate the DPRK with the cyberattack cannot be interpreted in any other way than a wicked attempt to lure the international community into harboring greater mistrust of the DPRK,” the spokesperson said in an article published by Pyongyang's Korea Central News Agency.