South Korean investigators are blaming North Korea for a series of hacking attacks on Seoul's nuclear power operator.
South Korea says Pyongyang is behind cyber attacks on Korea Hydro and Nuclear Power that took place in December. In December and again last week, hackers published on Twitter blueprint and test data believed to belong to the company.
The South Korean government said Tuesday the codes used to hack into the nuclear plant are the same codes used by North Korean hackers.
The nuclear hackers, using protocols based in China, sent some 6,000 "phishing" emails to 3,571 employees of the nuclear company.
The company said in December that it had been hacked, but said only non-critical data was taken.