Noting that there was scarcely any country which was not affected by terrorism, Antony said the recent terror-related incidents in Pakistan and Afghanistan have ''thrust South Asia into a sub-conventional conflict and instability.''
"Threat of nuclear weapons falling in wrong hands remains an area of serious concern and consequences of such a situation are unimaginable," he said while addressing a seminar 'Changing Nature of Conflict: Trends and Responses'.
Speaking on the occasion, Army Chief General Deepak Kapoor said South Asia along with West Asia has emerged as "one of the epicentres of conflict and instability."
The Army Chief warned that the situation would "further worsen since there was neither any political or diplomatic unity nor any common ground to build a consensus to fight this new war."
"Territorial disputes, provocation by proxy wars, religious fundamentalism, radical extremism, ethnic tensions and socio-economic disparities are the hallmarks of South Asia," he added.
The Army Chief said that due to sub-conventional conflicts, nations may be forced to undertake interventions on "purely humanitarian grounds if the diaspora is under threat, sovereignty of nations being questioned such as attacks on missions abroad and national assets and foreign soil being used constantly for attack by state and non-state actors."
Observing that space and cyberspace have allowed wars to be unleashed from drawing rooms, Kapoor said there was a need to re-examine the very concept of national security.
"There is definitely a need to evolve concepts and doctrine to protect nations' interests within and beyond the national boundaries as well," he added.
In a reference to the situation in India's western neighbourhood, the Army Chief said, "in some countries, conflict has reached almost every household and is no more restricted to borders or traditional warzones."
Citing example of Afghanistan and parts of Pakistan, the Army Chief said battlefields were merging as "going after the poppy cultivator and heroin smuggler may go concurrently with a war on militant fundamentalist groups, in an era when drug money finds its way into terrorist wars."
Kapoor said that though it was still not certain the way in which the 21st century would shape up but "one thing we know for sure is that it is a period, which will see constant turmoil -- a period of neither war nor peace."
Talking about the 'super-empowered individual' phenomenon, Kapoor said the individual has been empowered in an unprecedented way by computers to do things that he could never do before.
"In previous times, countries fought countries. Now groups fight countries, individuals fight countries; it is a different type of game altogether," he said.
On the steps for combating terror, the Defence Minister said there was a need for nations to initiate forward-looking responses and to be unified and collective in their fight against terror.
The Army Chief said multilateral military coalitions, preferably under UN aegis, will be an inescapable requirement in the future in dealing with terrorism threat.
He added that while nations would agree to work together towards conflict resolution, clash of interests may warrant nations to fight some conflicts in isolation for which they need to "build capability and capacity."