Afghanistan is "mission possible", the head of Nato has said in an effort to encourage hesitant members of the pact to boost their commitment to the area.
A number of countries refuse to fight in southern Afghanistan
Despite a strengthening Taleban, Jaap de Hoop Scheffer insisted the alliance could succeed in its Afghan mission and even start pulling out by 2008.
He spoke before a Nato summit in Latvia where the Afghan mission, Nato's first outside Europe, is due to dominate.
US President George Bush has also urged members to rise to the challenge.
"Member nations must accept difficult assignments," Mr Bush said on a stopover in Estonia. They must "provide the forces Nato military commanders require."
Mr de Hoop Scheffer has repeatedly warned that unless nations such as France, Germany, Italy and Spain drop the caveats that keep their troops out of the most dangerous areas of Afghanistan, the country would again become "a black hole for terrorism''.
But on Tuesday he was also keen to strike an upbeat note.
"We need to be frank about the risks," he said, "but we also need to avoid overdramatising."
And if sufficient progress were made, he said, Afghan security forces could start taking over as early as 2008.
Bearing the brunt
Nato-led forces have faced fierce resistance from Taleban militants in the south of the country in recent months, where violence has risen to heights not seen since the toppling five years ago of their authoritarian regime.
About 90% of the casualties suffered by troops serving with the Nato force have involved just four countries: the US, Britain, Canada and the Netherlands.
Germany, France, Spain and Italy all have troops in Afghanistan but they are confined to the more peaceful areas.
The summit is also expected to debate Nato's continuing role as a military alliance in the 21st Century.
"There are still too many messages of the Cold War in the way Nato is structured," said Mr de Hoop Scheffer, adding that partnerships with nations around the world "hold much potential".
"The decisions I expect from our summit here should help us unlock this potential".
MAIN FLASHPOINTS IN AFGHANISTAN
There are 32,500 Nato-led troops in Afghanistan
Main troop contributors: US, (11,800), UK (6,000), Germany (2,700) Canada, (2,500) Netherlands (2,000), Italy, (1,800) and France (975)