Anti-India elements in Pakistan are planning to attack Indian computer networks, intelligence agencies have warned.

Pakistani hackers are trying out a dry run by hacking popular websites registered there, home ministry sources said on Tuesday.

"Every time the relations between the two countries dampen, Pakistanis start attacking Indian computer networks and this has increased after the Mumbai terror attacks [Images]," a home ministry source said.

Pakistani hackers have created websites such as the www.songs.pk, which are infested with software to hack data from the targeted computers, it said.

"The website www.songs.pk has over 12 lakh Indian users who are downloading stuff from these websites daily," said a cyber expert in the ministry.

With these websites being highly popular, it will take only a few minutes for the hackers to take command of over 12 lakh computers in few minutes and the number of such computers can multiply in every minute, sources said.

"Instead of the existing less harmful virus, new ones such as Botnet and Zoombie can be easily released into the Indian computers, which later on replicate and make the entire server vulnerable," the expert said.

"Nowadays new virus and worms are detected while downloading songs from these websites, which could be just a dry run to manage a bigger attack," he said.

Indian government's websites have proved to be vulnerable in the past.

"Most of the time, these cases are not reported as the server is based in Pakistan and we cannot do anything in this regard," the expert said.

The anti-virus software, too, cannot work in such situation as the virus used in such cyber wars are usually new and the anti-virus software cannot identity and detect it, he said.

"If anti-virus software cannot identify the signature of the virus coming through Internet, it will not detect it and as a result the virus will be downloaded in the computer in spite of such software available in the network," the expert added.