"There is a likelihood of attempts (by terror groups) to disrupt the forthcoming Lok Sabha and assembly elections. The security forces need to be careful," the Prime Minister said while addressing a conference of country's top police brass here.

Referring to the recent communal clashes in Muzaffarnagar and adjoining districts in Uttar Pradesh which claimed many lives and displaced thousands, Singh said law and order agencies must ensure that trivial or local issues are not exploited by vested interests to inflame communal passions.

"During the current year some states have witnessed a substantial increase in the number of communal incidents. We cannot afford such a state of affairs.... Once disturbances occur they must be tackled with utmost firmness, without prejudice, fear or favour," he told the conference of Directors General Police and Inspectors General of Police.

The Prime Minister said state DGPs have the responsibility to ensure that their police force acts in the required manner in preventing communal actions.

Expressing concern over misuse of social media for fanning tension in the society, Singh said the country has witnessed misuse of social media and SMSs during the recent disturbances in Muzaffarnagar and also last year.

"There is a need to find creative solutions which do not curb the freedom of expression and the ease of communication that social media provides," he said.

The Prime Minister said resurgence of terrorist groups, particularly Lashkar-e-Taiba and increased infiltration attempts call for heightened vigil and coordination.

Congratulating the Intelligence Bureau (IB), which organised the conference, Singh said it was the intelligence gathered by the IB that led to the arrest of some suspects of several terror attacks.

Referring to the Maoist problem, the Prime Minister said it was important that the security forces do not let up on their efforts to root out the menace of naxalism and continue to build on the successes.

"Our intelligence, police, para-military forces have done commendable work during polls in the naxal affected areas of Chhatisgarh," he said.

Singh also said there was a need to improve the quality of governance and the pace of development in the naxal affected areas.

Earlier, Singh released the first ever commemorative postage stamp on the Intelligence Bureau logo - 'Awake, Day and Night'.