Taliban closing in on Kabul: report

While Iraq is showing the first signs of an improvement in security, Afghanistan's situation is becoming more precarious, Senlis argued, underlining the need for a rapid increase in troop numbers in a country that is larger than Iraq.

"In order to prevent NATO's defeat at the hands of the Taliban, a rejuvenated 'coalition of the willing' is needed," the report said, calling the proposal 'NATO Plus'.

"Every NATO state is mandated to contribute to this new force, with a firm level of commitment that will provide a total force size of 80,000."

Bolstering NATO's presence in Afghanistan, and getting member countries to contribute more, is expected to be a major issue on the agenda at a NATO summit in Romania in April.

Before then, Britain, which is responsible for security in the restive south of Afghanistan, where violence has been greatest, is expected to unveil new security strategies, including a possible increase in troops and proposals to deter Afghan poppy farmers from selling their crop to the Taliban.

Senlis said that without the troop "surge," and renewed efforts to win over the Afghan population and make reconstruction take hold, the country was in danger of falling back into the hands of the Taliban. Reuters