By David Loyn
BBC News, Kabul
The Nato Secretary General Jaap de Hoop Scheffer is in Afghanistan as the military alliance faces unprecedented tension over its mission there.
There have been increasingly visible strains in the Afghan mission
Many of the nations with troops in Afghanistan prevent them serving in the most dangerous areas in the south.
Forthcoming elections in Canada and the Netherlands, two of the nations who do send troops to fight in the south, could raise further questions.
But Mr de Hoop Scheffer denied tensions over the mission would destroy Nato.
Canada has already signalled that it will have to pull its troops out next year if more forces are not sent to Kandahar, scene of Afghanistan's worst suicide attack when 80 were killed on Sunday.
Speaking on his plane to Kabul, Mr de Hoop Scheffer told the BBC that he was "following the Canadian debate with great interest".
He said that that he was not happy about the "caveats" - the limitations on troop deployment imposed by some countries - but that he was a realist and realised that "we do not expect soon to see Germans or Italian forces in the south, except for the occasional emergency".
He said he was trying to convince some countries to send more troops, but that it was best done privately.
In recent weeks the US Defense Secretary Robert Gates has made a series of very public speeches, warning that if Nato was allowed to become a "two-tier" organisation, with only a few countries willing to put troops in harm's way, then that "would in effect destroy the alliance".
While preferring a more discreet debate about this issue, Mr de Hoop Scheffer denied that the tensions over the Afghan mission would destroy Nato.
"In my long career, Nato has been declared terminally ill or dead six or seven or eight times. So I am not worried about that," he said.
"I am also not worried that we are losing in Afghanistan. We are not losing. The challenges are huge, but we are not losing. We are making tremendous progress."
He said that the important thing was to improve training of Afghan troops and police, as well as better training for Nato troops in counter-insurgency warfare.
There has been an increasing emphasis from the international community in recent months in Afghanistan on securing political progress as well as fighting insurgents.
The expulsion of two European diplomats, and President Hamid Karzai's very public row with Britain and blocking of the appointment of Lord Ashdown as UN envoy, all testify to strains over the speed of progress.
Mr de Hoop Scheffer said that President Karzai realised the need for dialogue with some Taleban elements, but "it is his nation not ours.
"I think he realises very well that in Afghanistan some sort of political process has to take off. You do not of course talk to people who are beheading people and hanging them and burning schools.
"But everywhere in the world where there is a conflict at a certain stage, a form of political process has to start."
ISAF REGIONAL COMMANDS AND RECONSTRUCTION TEAMS
Countries contributing more than 1,000 troops (6 February 2008):
Australia - 1,070
Germany - 3,210
Italy - 2,880
Netherlands - 1,650
Poland - 1,100
UK - 7,800
US - 15,000