"History has taught us that peace, security and prosperity are indivisible. That is why the evolution of Afghanistan as a stable and moderate nation state is so vital for the region and the world," he said Monday while addressing the Council on Foreign Relations, a leading US think tank.
"The road to peace in Afghanistan will be long and hard. But, given the high stakes involved, the commitment of the international community must be sustained by firm resolve and unity of purpose," he said.
Asked if the results in Afghanistan would be decisive for Pakistan, Manmohan Singh said: "I have no doubt in my mind that if Taliban and Al Qaeda group of people succeed in Afghanistan that would have catastrophic results for the security and stability not only of Pakistan but also for the security and stability of whole South Asia."
Apart from the 1.8 billion people living in South Asia, he said, it would "affect the course of evolution in the Middle East, Central Asia and maybe I think beyond these regions as well".
Manmohan Singh declined to interject in the ongoing debate in the US on the right size of troops that need to be deployed in Afghanistan as he was not an expert on military affairs.
But, he said: "I am clear in my mind that Afghanistan requires the sustained support of global community if it is to return to a path of peace, freedom and an environment in which fundamentalist and terrorists elements do not have the sway of the type they had some years ago before 9/11."
Addressing Pakistan's perceived concerns about New Delhi's role in Afghanistan, the prime minister said India has enduring civilisational links with the country and "we do not see Afghanistan as a theatre of influence".
"Our interest is in building a region of peace and stability. India will continue to assist Afghanistan in building its institutions and its human resources," he said.
Noting that democracy in an ancient land like Afghanistan would take time to take root, he said: "It is vitally important that all major regional and international players put their weight behind the government of Afghanistan. This is the only way Afghanistan can meet the daunting challenges it faces."
