Afghanistan is falling back into the hands of the Taleban, a report by an international think-tank has claimed.
The report said foreign troops had failed to create stability in the region
The Senlis Council has blamed international forces for failing to achieve stability and security.
But the British Foreign Office has rejected the report, insisting progress has been made in the country.
And Nato troops say they have "trapped" the Taleban, adding at least 50 rebels have been killed on the fourth day of an offensive in the country's south.
The Senlis Council, which provides advice on foreign policy, security and development, claims nothing has been done to address widespread poverty in Afghanistan.
Its report, Afghanistan Five Years Later: The Return of the Taleban, says that the Taleban have a strong psychological and de facto military control over half of the country.
"Nato is caught in a trap in a way. They are faced with a deteriorating situation, they cannot do the core job of helping reconstruction," Emmanuel Reinert, executive director of the Senlis Council, said.
But a spokesman for the British Foreign Office said progress had been made with the introduction of parliamentary and constitutional organisations.
"We do not recognise the picture they are trying to paint, " he said.
Also in contrast to the report's claims, Nato forces say their offensive is working to corner the Taleban.
"We are closing the circle on the Taleban, we have got the Taleban in a bit of a trap," Nato spokesman Major Quentin Innes told the Reuters news agency.
Nato forces have clashed with rebels in the Panjwayi district, about 35km (20 miles) west of Kandahar city.
The offensive is part of Operation Medusa, which began over the weekend and is designed to flush out hundreds of Taleban fighters.
Meanwhile, the Secretary General of Nato, Jaap de Hoop Scheffer, is currently visiting Afghanistan.
He is assessing progress in efforts to stabilise the south and will meet Afghanistan's President Hamid Karzai on Wednesday.