Nato leaders at a summit have hailed the relaxation of curbs on deployment of some members' troops in Afghanistan.
Canada has had dozens of troops killed in Afghanistan
Nato commanders say they believe they can move an extra 2,500 troops around the country now some smaller members have relaxed their mission conditions.
But France and Germany will not move to the volatile south. They say they are only prepared to help in an emergency.
The US, UK, Canada and the Netherlands have borne the brunt of fierce fighting with Taleban militants in the south.
Violence has risen to heights not seen since the toppling of the Taleban in 2001.
Some 4,000 people are believed to have died this year in the insurgency - about a quarter of them civilians.
In fresh violence, two Nato soldiers were killed when their vehicle struck a roadside bomb in Logar province on Tuesday. The nationalities of the victims have not yet been released.
Nato chief Jaap de Hoop Scheffer welcomed the relaxation of "caveats" on deployment in Afghanistan.
Nato's secretary general wants more troops for Afghanistan
He said about 20,000 of the 32,000-strong Nato force were now more usable for combat and non-combat missions.
"We have made real progress on caveats," he said.
Correspondents say the combat curbs have been the most contentious issue at the two-day summit in Latvia, following tension over the reluctance of France, Germany, Spain and Italy to send their troops to southern Afghanistan.
Those agreeing to ease the restrictions on deployment against the Taleban include the Dutch, Romanians and smaller nations such as Slovenia and Luxembourg.
France, Germany, Spain and Italy have said they will now send help to trouble zones outside their areas, but only in emergencies.
The Nato chief welcomed the small shift.
"In an emergency... they will support each other," he said. "That is the most fundamental demonstration of Nato's solidarity."
The summit also saw several countries offer additional troops and training teams, while France agreed to send more helicopters and aircraft.
UK Prime Minister Tony Blair told the BBC the summit had made significant progress towards generating enough force to defeat the Taleban, but they still "need to make those last remaining steps".
But a foreign office minister was more critical of the effort.
"This view seems to say it's all right for British soldiers to die in defence of the West but it's not all right for other soldiers," Kim Howells said.
No new members
The summit, the first Nato meeting in an ex-Soviet state, also discussed its partnership activities.
The alliance issued an invitation to Bosnia-Hercegovina, Montenegro and Serbia to join the Partnership for Peace programme.
But the summit communique reiterated Nato concerns that Serbia and Bosnia-Hercegovina should co-operate with the International Criminal Tribunal for the former Yugoslavia and help to bring alleged war criminals to justice.
They also pledged to boost training with countries around the Mediterranean and in the Middle East.
No new member countries were invited to join, but the secretary general said Nato's door remained open - and every effort would be made to assist aspiring members over the threshold.
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)