Indian Prime Minister Manmohan Singh has said that intelligence agencies have warned that more terrorist attacks were likely in the country.
Mr Singh said terrorists may attack religious and economic targets
Mr Singh said that that "economic and religious targets", as well as nuclear installations, could be the targets.
He said the intelligence agencies have also warned of more suicide attacks.
Mr Singh's comments come nearly two months after a series of bombings on commuter trains in Mumbai (Bombay) which killed over 180 people.
"Concern about the increasing activities of externally-inspired and directed terrorist outfits in the country is justified," Mr Singh told an internal security meeting in the capital, Delhi.
"Intelligence agencies warn of a further intensification of violent activities on their parts."
Mr Singh said that "reports also suggest that terrorist modules and 'sleeper cells' exist in some of our urban areas, all of which highlight the seriousness of the threat".
Referring to the security situation in Indian-administered Kashmir, the prime minister said that "though the situation has shown signs of improvement in these past two years, we should remain on our guard in view of continuing efforts by anti-India and anti-national elements to whip up emotions and transform these into a violent movement".
Militant groups have been fighting an insurgency against Indian rule in Kashmir since 1989. The conflict has cost over 60,000 lives.
Mr Singh said the government favoured a "blend of firm, but sophisticated, handling" of the problem of violence by Maoist rebels in India.
"It is in the most neglected areas of the country that Left wing extremism thrives today," he said.
Nearly 6,000 people have been killed in violence linked to Maoist rebels in several southern and eastern states over the past 20 years.
The rebels are pressing for the creation of a communist state comprising tribal areas in the states of Andhra Pradesh, Maharashtra, Orissa, Bihar and Chhattisgarh.