A Nato summit in the Latvian capital has failed to muster significant reinforcements for operations in Taliban strongholds in Afghanistan.
Allies such as France, Germany, Italy and Spain declined to send troops to regularly fight on the front lines against the Taliban in the south and east of the country.
But officials said all 26 Nato members had agreed to lift national restrictions, or "caveats", on the movements of their troops to allow them to assist allies when in trouble.
Polish President Lech Kaczynski said: "The summit did not have the character of a major breakthrough."
"Not all countries showed the same level of determination," he said.
Presently only the US, Britain, Canada and the Netherlands allow their troops to be sent into the Taliban's heartlands where recent fighting has been heaviest.
They argued that the Europeans' limits on troop deployments meant that only a few of the Nato allies deployed in Afghanistan were taking the brunt of casualties there and risked undermining alliance solidarity and public support for the mission.
Tony Blair, the British prime minister, said: "These have been significant steps in the right direction ... Have we got absolutely everything we wanted? Not yet."
Jaap de Hoop Scheffer, the Nato Secretary-General, dismissed those who were pessmistic about the fighting in Afghanistan: "There is not the slightest reason to voice gloom and doom over Afghanistan."
Nato officials said at least three nations offered to send more troops to bolster the 32,800-strong allied force presently in Afghanistan.
They did not name them, but Vaclav Klaus, the Czech president, announced that his country would boost its military presence in Afghanistan by 50 per cent, to 225 soldiers, next year.
Jacques Chirac, the French president, said France planned to send more helicopters and warplanes.
French officials said he would also allow troops to operate beyond their base in Kabul, the Afghan capital, when needed.
Nato also declared that a new 25,000-member rapid-response force designed as the spearhead of a modernised Nato military is ready for action after four years of preparation.