South Korea steps up cyber security at nuclear plants

SEOUL (Reuters) - South Korea boosted cyber security at the country's nuclear power plants on Tuesday following what President Park Geun-hye described as a series "grave" data leaks, and prosecutors said they were investigating a new online threat.

Korea Hydro and Nuclear Power Co Ltd (KHNP), which runs South Korea's 23 nuclear power reactors, said on Monday its computer systems had been hacked, raising alarm in a country that is still technically at war with North Korea.