TAIPEI: The author of the Chernobyl computer virus said yesterday he created the bug hoping to humiliate and take revenge on what he called incompetent antivirus software providers, but he did not expect it to cause such great worldwide damage.

Chen Ing-hau, 24, looked nervous and was speechless when he was mobbed by reporters after being summoned into the Bureau for Criminal Investigation for questioning on his involvement in a case that caused at least 600,000 computer meltdowns.

Police described the Chernobyl virus--known in Taiwan as the CIH, using Chen's initials--as the first Taiwan-originated computer virus that ever caused worldwide damage.

The Chernobyl virus had even pressed the Chinese People's Liberation Army to study antivirus programs to prevent it from invading its computers, a police statement said.

Some Chinese computer users had compared the virus' havoc to the Nanjing Massacre committed by the Japanese troops in World War II, the statement said.

Chen created the virus last April when he was a senior student of computer engineering at the Institute of Technology.

Chen has since graduated and has been undergoing Taiwan's mandatory two-year military service.

Chen had spent long hours playing the computer since entering college and was a frequent victim of computer viruses when downloading video games and other software from the Internet, the police statement said.

"He said he created the highly vicious virus that could avoid detection by available antivirus programs in order to make a fool of the software providers, from whom he had bought antivirus programs that proved useless," the statement said.

"He did not expect the virus to cause such a great impact. He regretted his deeds and apologised to all victims."

The unusually destructive virus--timed to strike on April 26, the 13th anniversary of the Chernobyl nuclear disaster--tries to erase a computer's hard drive and write gibberish into its system settings to prevent the machine from being restarted.

Turkey and South Korea each reported 300,000 computers damaged on Monday, and there were more elsewhere in Asia and the Middle East. Damage was less extensive in the United States.

Chen's former professors said he placed the virus on the Internet to boast his ability, not to cause computer meltdowns.

He was given a demerit but the college did not mete out a more severe punishment because Chen had warned fellow students not to spread the virus, the professors said.

Under Taiwan law, someone convicted of spreading computer viruses can face up to three years in prison.