The threatened withdrawal of European troops from Afghanistan puts at risk NATO’s mission to eradicate the Taliban and prevent the return of Al Qaeda, Defense Secretary Gates will warn his counterparts at a NATO summit opening in the Netherlands tomorrow.

Unless European countries can commit more forces and equipment without delay, America will begin to withdraw troops from Kosovo, the troubled province of Serbia, and transfer them to Afghanistan, Mr. Gates will announce.

The Canadians, the Dutch, and, since the election of a new prime minister yesterday, the Poles have all expressed their intention of withdrawing, reducing, or reallocating their military personnel from the Afghan front line, to the frustration of the American, British, and Australian administrations, whose forces largely bear the brunt of the fierce fighting with the Taliban.

Mr. Gates expressed his frustration at the Europeans’ apparent lack of commitment to the Afghan cause yesterday at a meeting of southeastern European defense ministers in the Ukrainian capital, Kiev, where he was trying to persuade the new pro-Western government of Ukraine to send forces to Afghanistan.

“I am not satisfied that an alliance with members who have over 2 million soldiers, sailors, marines, and airmen cannot find the modest additional resources that have been committed for Afghanistan,” Mr. Gates told journalists.

Mr. Gates’s appeal for more troops and matériel to fight the Taliban will be repeated tomorrow by the secretary-general of NATO, Jaap de Hoop Scheffer, at the two-day meeting in Noordwijk, Netherlands, where representatives of the alliance’s 37 nations will discuss the future of the 41,000 troops serving in Afghanistan.

“From a NATO point of view, 90%–95% of what we want is on the ground, but we need more helicopters, we need more transport aircraft, and we need what we call more maneuver capabilities. Most of all, we would like more trainers from the NATO nations. In the end, the Afghans are going to have to fight their own fight, and the way that happens is if we help train and equip them,” Mr. Scheffer’s spokesman, James Appathurai, told the BBC.

The shortage of helicopters appeared to have been overcome yesterday. Bloomberg News reported that NATO will lease about 20 transport helicopters for use in Afghanistan to shuttle equipment and ammunition. The arrangement will free up an American helicopter unit in Kandahar to resume front line duties: combat, transporting troops, and ferrying wounded soldiers.

Making up the shortage of trainers of recruits to the Afghan military and police forces is more difficult. The estimated shortfall of trainers is more than 3,000, but many NATO members seem reluctant to provide even these noncombatant personnel.

The much trumpeted arrival of French fighting troops in Afghanistan, after the election of the pro-American President Sarkozy, who is seeking to rehabilitate France’s membership in NATO, has sputtered to a halt after Taliban terrorists kidnapped five aid workers and demanded that the French withdraw. Mr. Sarkozy has since agreed to allow his forces to train Afghan troops.

Even more critical than training is the growing number of countries hesitating about deploying fighting forces. The Iraq war has put a strain on the ability of some NATO countries to participate fully in Afghanistan. “Pressures on troop numbers in all of our nations are exceptionally high,” the NATO assistant secretary general for defense policy and planning, John Colston, said at a news conference in Brussels yesterday.

The Dutch still have to decide whether to withdraw their combatant troops at the end of their mission next year. The Canadians, who supply 2,500 troops to fight in Afghanistan, are deciding whether their troops should become noncombatant.

The new Polish prime minister, Donald Tusk, suggested during the election campaign that he would withdraw troops from both Afghanistan and Iraq. He replaces a prime minister who was eager to provide Polish troops to fight in Afghanistan. The imminent election in Australia may also remove a government that has solidly backed NATO’s efforts in Afghanistan.

The official NATO line is that some of the threatened reductions in forces may never be carried out. “In the south, we don’t think the Dutch are going to leave. The Canadians are looking at exactly what they can do. The British are talking in the south not only about keeping what they have but potentially increasing it,” Mr. Appathurai said. “We are not pessimistic at all. We hope the Dutch will stay, we hope the Canadians will stay, and we are working to convince them to do that in one form or another.”

A British government defense spokesman promptly denied to reporters that Prime Minister Brown would redeploy to Afghanistan the 1,000 British troops soon due to leave Iraq.

One issue likely to be raised tomorrow that is hindering the smooth running of NATO efforts in Afghanistan is the continuance of “national caveats” that limit how troops from a nation are used, such as whether they can be used for fighting, support, or merely humanitarian missions. “We would like to see national caveats dropped,” Mr. Appathurai said.