Shanghai, March 22 (Xinhua) Chinese computer experts are warning Internet users that two new strains of existing computer virus could be on the attack.

The two new strains are based on the notorious and destructive viruses known as 'Panda burning joss stick' and 'Qiuying'. Anti-virus experts suggest users upgrade their anti-virus software immediately.

DQ (Worm.WhBoy.dq), a mutation of 'Panda burning the joss stick', could infect executive files and websites and terminate the monitoring programs of many anti-virus software. It can also hijack Internet Explorer and automatically download new mutations of the virus.

'Qiuying B', a stealthy and insidious computer virus can cause blackouts and dramatically slow the operation of computers.

Chinese cyber space was frequently hit by malicious computer viruses last year. The 'Panda' virus was listed as the worst computer virus by Chinese anti-virus company Rising.