WASHINGTON—The United States is scrambling to coax NATO allies to send 10,000 additional troops to Afghanistan as part of President Barack Obama's strategy for the region. Those countries appear willing to provide fewer than half that number, U.S. and allied officials said Wednesday.

NATO and other foreign allies have expressed reluctance to send more soldiers because of the Afghan war's growing unpopularity in their countries and increasing concerns over corruption in President Hamid Karzai's government.

The Obama administration views a substantial contribution from its allies as a way to keep the U.S. troop increase lower and blunt domestic political criticism of the Afghan war. It would also allow the administration to come close to the military's request for 40,000 additional troops without relying totally on the already stretched U.S. armed forces.

After weeks of deliberation, Obama will formally announce how many extra American troops he will commit to Afghanistan in a national address on Tuesday. Administration officials say that a strong speech, explaining Obama's strategy for achieving success, would provide them fresh ammunition to galvanize support in foreign capitals.

In Britain, which has pledged an additional 500 troops, Defense Secretary Bob Ainsworth said on Tuesday that Obama has taken too long to decide on a new strategy, harming his government's ability to rally public support for the war.

The British government is facing opinion polls showing that around 70 percent of the public favor an early withdrawal. That figure that has just about doubled in the past six months, as the country has sustained its worst casualties—97 killed so far this year—since it first deployed troops to Afghanistan after the Taliban were toppled in November 2001.

Germany and France have balked at committing any more forces to a war that has so little public support they can barely maintain current troop levels.

The Netherlands and Canada have begun discussing plans to pull out. Canadian defense officials told reporters traveling with Defense Secretary Robert Gates in Halifax last week that they had no intention of sending troops in the future, and that they remain committed to withdrawing by the end of 2011.

Even if the allies make commitments for 5,000 or more new troops after the president's address Tuesday at West Point, NATO officials say, those commitments will include troops already in the country to provide security for recent elections as well as trainers for the Afghan army and police.

And it remains unclear whether several thousand NATO and other foreign troops are really the equal of a similarly sized U.S. force in terms of military capability. Some countries may continue to impose restrictions on how their forces may be employed.

In addition, a force that is cobbled together from too many nations—a few hundred here and a thousand there—might not have the unit cohesion of an American force, military analysts said.

Washington has not yet made formal troop requests to allies, but there have been diplomatic and other conversations seeking commitments in principle, carried out by senior U.S. officials; the NATO secretary-general, Anders Fogh Rasmussen; and Prime Minister Gordon Brown of Britain.

Obama's aides have signaled that he intends to commit close to 30,000 additional U.S. troops, on top of the 68,000 already there.

The president is likely to ask NATO allies to fill the gap between whatever new U.S. troop contribution he announces and the approximately 40,000 that the NATO commander in Afghanistan, Gen. Stanley McChrystal, favors to carry out his proposed counterinsurgency strategy, according to administration officials. The officials spoke on the condition of anonymity because the policy has not been formally announced.

After Obama gives his speech and Rasmussen delivers a statement of support, NATO foreign ministers will meet in Brussels on Thursday and Friday to discuss Afghanistan. But troop commitments are not likely to be discussed in detail before a so-called “;force-generation conference”; on Dec. 7, also in Brussels, U.S. and allied officials said.

Informal commitments of several thousand additional allied troops have already been made, but they include some of the extra 10,000 European troops that were sent to Afghanistan by governments last year, as well as troops sent for the recent presidential elections, NATO officials said.

A senior NATO official said that countries planning to pull troops out will also come under pressure to allow the soldiers to remain.

Rasmussen spent Wednesday in Rome, for instance, talking to the Italian government on this very topic, and Italy appears ready to send more troops, officials said. He has also been to Warsaw, which officials said will contribute more troops.

Brown said on Wednesday that he is “;now optimistic,”; after canvassing allies, that a number of countries “;will indeed make available increased numbers of troops, and more police trainers and civilian support.”; He said he hoped the figure would be 5,000 troops.

Other NATO officials said that the figure is roughly accurate, even low. With new contributions expected from Poland, Italy and Britain, the major exceptions for the moment are Germany and France, the officials said.

Georgia, which is trying to secure its ties and future membership in NATO, has agreed to send another company, officials said, and may end 2010 as the largest non-NATO contributor.

France, however, is standing firm on its refusal to consider sending more troops beyond the 3,750 now in Afghanistan. Paris increased its troops by a battalion of 800 last year, added another 200 this year, and plans to send another 150 gendarmes to help train the Afghan police, said Christophe Prazuck, a spokesman for the French military.

From Nov. 1, France has also redeployed its troops out of Kabul into a new task force with 2,500 troops based east of the capital in Surobi and Kapisa. But President Nicolas Sarkozy told Le Figaro in mid-October that while NATO must stay in Afghanistan, “;France will not send a single soldier more.”;

The new German government has not committed to more troops, but Defense Minister Karl-Theodor zu Guttenberg has not ruled out an eventual increase. He told military leaders in Berlin on Tuesday that “;Germany will rethink and adjust, maybe even strengthen its military commitment to make Afghanistan a success.”;

The German mandate to keep its troops in Afghanistan is up for approval by Parliament in December. Right now the country has roughly 4,300 soldiers there. Guttenberg has steadfastly maintained that the government will not review the level of forces until after an international Afghanistan conference at the end of January, though he recently authorized an additional 120 soldiers to help deal with the worsening situation in northern Afghanistan, especially around Kunduz.