SEOUL, South Korea — South Korea says an initial investigation has found that North Korean government agents were behind a March cyberattack that shut down about 32,000 computers and servers at South Korean broadcasters and banks.

An official at South Korea's Internet security agency, Chun Kil-soo, told reporters Wednesday that the attack was similar to past North Korean hacking. He said investigators believe that six computers in North Korea were used to access South Korean servers using more than 1,000 IP addresses overseas.

The accusation comes as tensions run high on the Korean Peninsula, with North Korea delivering increasingly belligerent rhetoric in anger over U.N. sanctions and U.S.-South Korean military drills.

On Tuesday, the North said a nuclear war is imminent and recommended that foreigners in South Korea evacuate to safe places.