Continuing insurgency and the Afghan government's weakness make Western and European defeat in Afghanistan a realistic prospect, warns a report published by a London-based think-tank.

The report by the European Council on Foreign Relations, presented in Brussels Tuesday by its author, Daniel Korski, at an event organised by the Brussels-based think-tank European Policy Centre, says that six years of war and the biggest military operation in the history of NATO have failed to subdue the Afghan insurgency.

"A swift and successful end to the conflict is out of reach: even optimistic scenarios foresee an international presence in Afghanistan for years to come," according to the 35-page document quoted by EuAsiaNews.

The Taliban insurgency would continue to grow stronger as winter ends, it said.

Korski, a former advisor to the Afghan minister for counter-narcotics, called on the international community to encourage President Hamid Karzai to engage "moderate" insurgents by offering financial and other incentives to support the government.

He stressed that regional cooperation is vital for stability in Afghanistan.

"Any stability achieved in Afghanistan will remain unacceptably fragile as long as neighbours such as Pakistan, India, Russia and Iran treat the country as a pawn in their own regional power play."

The report sees it necessary to address the causes of Pakistan's quest for "strategic depth" - the fears of encirclement by India. India's support to Afghanistan is seen in Islamabad as part of a deliberate strategy to encircle Pakistan.

It suggests that the appointment of senior Norwegian diplomat Kai Eide as UN envoy for Afghanistan and the NATO summit in Bucharest this week provides a unique opportunity to craft a new international strategy for the country, led by political rather than military goals and driven by a regional and comprehensive approach.

Leaders of the 26-member alliance are expected to hold an in-depth discussion on Afghanistan during their three-day meeting in the Romanian capital.

Jamie Shea, director of policy planning in NATO, told the large gathering of diplomats, EU officials, experts and journalists that "we have to do better in the next five years than what we have done in the last five years".

Shea claimed that most of Afghanistan is relatively "calm, stable and secure."

Helen Campbell, head of unit for ties with Afghanistan and Pakistan in the European Commission, said only a long-term commitment and a comprehensive approach would lead to success in Afghanistan.

The EU's executive body remains one of the top donors in Afghanistan and one of the very few giving a multi-year commitment.