Officials said France, Germany, Italy and Spain had agreed to remove restrictions on aiding other countries' militaries in an emergency in Afghanistan. But the four nations will not be sending troops to regularly fight alongside the British, Canadian, Dutch and American forces on the front lines of battles with the resurgent Taliban in the south and east.
"The summit did not have the character of a major breakthrough," Polish President Lech Kaczynski said. "Not all countries showed the same level of determination."
British Prime Minister Tony Blair tried to cast the summit in a more positive light.
"These have been significant steps in the right direction," Blair said. "Have we got absolutely everything we wanted? Not yet."
NATO leaders pledged in a closing statement to stay the course in Afghanistan. Blair said it was crucial that they had agreed that the alliance must succeed.
NATO officials said they received assurances at the leaders' dinner Tuesday night that all nations would allow their troops in the 32,800-strong allied Afghanistan stabilization force in the nation to come to the aid of allied units in trouble anywhere in the country.
Officials said at least three nations, which they did not name, offered to send more troops.
President Jacques Chirac 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.
"There should be no doubt on our common determination to make a success of this mission," French officials quoted Chirac saying at the meeting. "In support and solidarity with our allies, France has decided to strengthen its contingent."
Nations with troops in the south and east have raised concern that limits on troop deployments risk undermining alliance solidarity and public support for the mission, while only some allies are taking most casualties.
"Losing young men and women is the surest way that can happen," Canada's Foreign Minister Peter MacKay said. Progress "can still be eroded ... if you have people coming home in coffins," he said.
Canada has suffered 44 fatalities in Afghanistan — 36 this year alone. Most occurred after NATO troops moved into the south this summer.
Leaders at the summit also declared that a new 25,000-member rapid-response force designed as the spearhead of a modernized NATO military is ready for action after four years of preparation.
Underscoring the dangers in Afghanistan, two more NATO soldiers were killed by a roadside bomb Tuesday south of Kabul. NATO did not immediately release the nationalities of those victims.
"Everyone accepts that this is NATO's absolutely critical mission," Blair said. "There's been a real sense that this mission in Afghanistan is not yet won but it is winnable and I think we are winning."
President Bush on Tuesday also raised the pressure on allies to ease restrictions on what their troops can do in Afghanistan.
"Afghanistan is NATO's most important military operation," Mr. Bush said. "By standing together in Afghanistan we will protect our people, defend our freedom and send a clear message to the extremists — the forces of freedom and decency will prevail."
NATO officials said leaders did agree on the need to follow up military operations in Afghanistan with speedy development aid and help to the Afghan government to build up the local police and judiciary, along with roads, hospitals and schools.
However, a new and possibly more difficult obstacle for Western leaders in Afghanistan is Iran's growing influence in the central Asian nation.
Iran is strengthening economic ties with western Afghanistan that could undermine support for U.S. and NATO forces.
Western Afghanistan has a newly paved 75-mile stretch of highway between the Iranian border and its main city, Herat, courtesy of the Islamic republic. Iran is also considering building a rail line on the busy route, and has pledged another $560 million to help rebuild Afghan infrastructure and businesses.
"Iran is not going away from here," a Herat-based Western diplomat said. "The question is whether we can coexist in this region together and realize that some of our aims might even be the same when it comes to Afghanistan."
Tehran has built 10 schools and built several clinics in western Afghanistan, and paid for the equipment to provide electricity 24 hours a day in Herat, unlike in most other parts of the country, including the capital, Kabul.
Iranian influence here dates back to ancient times and, while dependent on U.S. military and financial support, the Afghan government tries not to antagonize Iran, which currently houses about 2 million Afghan refugees.
"Our hope is for Afghanistan to be peaceful and stable because that would be good for the region," said an Iranian diplomat in Kabul, speaking on condition of anonymity because he was not authorized to speak with the media. "Everyone wants a stable neighbor."
If Iran and the United States are at odds, Defense Ministry spokesman Gen. Zahir Azimi said, "we will stay out of it."
Local political analyst Mohammed Rafiq Shaeir says Iran wants greater influence in western Afghanistan to promote its own national interests, both security and economic.
"The people of Herat have doubts about why Iran is putting so much attention into this area, but they still recognize that it is good for our own national interests and security in the region to have friendly relations with Iran," Shaeir said.
Saeed Laylaz, a prominent political analyst in Tehran, said Iran is investing in Afghanistan chiefly for its own national interests, rather than to counter Western influence.
"Regardless of presence of the NATO forces there, Iran has been always suffering from lack of stability in Afghanistan," Laylaz said in a phone interview. "An unstable Afghanistan would cause difficulties for Iran."