SEOUL, South Korea (AP) — A North Korea cyber warfare unit hacked into a South Korean military command earlier this year and stole some 2,000 national secrets, including information on toxic chemical makers, a news report said Saturday.

The North Korean unit hacked the army command in March and obtained its password for a database on how to respond to chemical accidents, Chosun Ilbo newspaper reported.

The report said the National Institute of Environmental Research, which set up the database, cut off its Internet link to the army command a day after the attack after being tipped off by South Korea's spy agency.

The state-run research agency said some 2,000 secrets, including information on about 700 local toxic chemical manufacturers, appeared to have been leaked, according to the newspaper.

The newspaper cited the November edition of its sister company's magazine, Monthly Chosun, noting the magazine obtained the information from the prime minister's office.

South Korea's spy agency, the National Intelligence Service, declined to comment, citing national security reasons. Calls to the prime minister's office, the Defense Ministry and the National Institute of Environmental Research seeking comment went unanswered Saturday.

A separate news report said the password was leaked when an army colonel's computer became infected with a virus while visiting an Internet portal site. The Yonhap news agency, citing an unidentified military official, said the South does not rule out the possibility of North Korea's involvement in the hacking attack.

South Korea's Defense Ministry said in May it was aware that the North has been training hackers in recent years.

North Korea, one of the world's most secretive countries, is believed to have a keen interest in information technology, while tightly controlling access for ordinary citizens.