Terming terrorism and Maoist violence as two major challenges facing the country, Prime Minister Manmohan Singh on Saturday said the Delhi high court blast was a stark reminder that there can be no let up in the vigil.

Singh said everyone must unequivocally send out a message that pursuit of violence cannot be justified under any circumstances and reaffirm the collective resolve to fight the menace of terrorism in all its forms with available means.

"The problems of terrorism and Left-wing extremism constitute two major challenges that our society and polity face today. The terrorist attack in Delhi last Wednesday is a stark reminder to us that there can be no let up in our vigilance," he said addressing the National Integration Council (NIC) meeting here.

The meeting was attended by senior Union ministers, chief ministers, Leaders of Opposition in Parliament, leaders of national and regional political parties among others.

"Time and again our nation has been subjected to terrorist violence. Terrorist seek to justify such violence based on misplaced sense of ideology," he noted.

The Prime Minister said no civilised society can tolerate or endorse loss of innocent lives in the pursuit of any ideology and institutions and instruments of the country's democratic polity allow sufficient opportunity for articulating differing view without resorting to violence.

Singh stressed on the need to identify and address the causes of radicalisation of some of the country's youth.

"Very clearly, lack of productive employment opportunities for our young men and women is one factor which aids such radicalisation. Education and skill development opportunities have a major role to play in addressing this problem," he said.

Referring to steps being taken to strengthen security agencies, Singh said there was a need to continuously upgrade and strengthen investigating agencies and the intelligence gathering apparatus to deal more effectively with the newer methods and technologies that the terrorists and Naxals adopt.

Noting that government has tried hard to strengthen the country's security apparatus, he said, "The intelligence sharing mechanism under the Multi-Agency Centre has been bolstered and the National Intelligence Grid is being implemented so that intelligence from various sources can be accessed and analysed to identify actionable points".

The Prime Minister said the problem of Naxalism has a development dimension also and the Centre is making special efforts for development of backward areas, many of which are affected by Left-wing extremism.

"The Central and state governments have to work together to confront the challenges to our internal security and we will strive hard for greater coordination not only between the Centre and states but also between states," he said.

Referring to civil disturbances, which is one of the agenda items of today's meeting, Singh said one should keep in mind that excessive use of force often proves counter- productive.

"We need to distinguish between criminal activities and misguided discontent that finds unlawful expression. It is with this intent that the home ministry has circulated instructions for dealing with crowds in a non-lethal manner," he said.

He urged the chief ministers to ensure that these are made operational by appropriately equipping and training the police forces.