The government today said it had warned the defence services, financial institutions, PSUs, Internet service providers and prominent private sector organisations of a possible cyber attack by Pakistani hacker groups.

In a written reply to the Rajya Sabha, Minister of State for Telecom and IT Sachin Pilot said, "Intelligence agencies recently issued a warning against large scale cyber attacks by Pakistani hacker groups from March 31, 2010, to April 6, 2010, targetting websites of Indian organisations."

During the said period, a total 330 websites were defaced. However, only four websites belonged to government organisations.

The Indian Computer Emergency Response Team (CERT-In), which detects cyber security threats, has already issued an advisory circulated to all Chief Information Security Officers (CISO) in the government and prominent private sector organisations.

Pilot said that the ministries and departments have been advised to audit their IT systems regularly to ensure robustness of their systems.

The government has formulated a Crisis Management Plan for countering cyber attacks and cyber terrorism, which is under implementation by all ministries and departments of the central government and state governments and critical sectors, he added.

To another query about the health hazards related to telecom towers, he said that sectoral regulator TRAI plans to float a consultation paper on the issue.