Gates, in Poland for NATO talks, says the economic crisis and the wars in Afghanistan and Iraq have taken precedence. He says Washington needs a little time to look at the plan laid out by former President George W. Bush to place missile interceptors and radar in Poland and the Czech Republic as protection against a possible strike from Iran.
Poland is one site for a planned U.S. missile shield system that Russia has aggressively protested.
Gates, the lone holdover from the Cabinet of Republican George W. Bush, added caveats to his once ample support of the missile defense plan. The idea was a Bush favorite, but President Barack Obama has not been a vocal supporter of the program.
Still, he hasn't indicated he would cancel it, either; the administration says it wants to make sure the system is reliable and doesn't detract from other security priorities. That has been seen in Europe as a sign that the plan could be scaled back or scrapped.
Gates says he asked his Polish counterpart for patience as the new team gets settled.
Gates did sign a new military cooperation agreement with Poland on Thursday, formalizing ties between the special forces operations of both countries. Gates praised Poland's willingness to send troops into harm's way, including about 1,600 in Afghanistan.
"As an old Cold Warrior it is a true honor to be able to sign this document on behalf of the United States," Gates told Polish Defense Minister Bogdan Klich.
"We have to wait as the American administration works out its view on the future of the missile defense project," Poland's Klich said after the meeting.
"What's left for us to do: To underline and remind people that Poland accepted the American proposal, that last year a deal was signed ... and that the agreement binds both sides, and I stressed that during today's talks," Klich said on TVN24 television.
NATO's agenda, however, is dominated by concerns about a resurgent Taliban insurgency and logistical problems in the NATO-led Afghanistan war. The United States is the largest contributor to NATO's force of 50,000, and has troops stationed in Afghanistan separately. Mr. Obama this week approved sending another 17,000.
NATO's secretary-general said Thursday that efforts to defeat the Taliban in Afghanistan were not succeeding, but alliance members produced no new public pledges of support despite urging from U.S. Defense Secretary Robert Gates.
NATO spokesman James Appathurai said alliance defense ministers meeting in Krakow, Poland, had welcomed the Obama administration's plan to send 17,000 more U.S. troops to shore up the 65,000 international troops - half of them Americans - fighting resurgent Taliban rebels.
But Appathurai said alliance members would not likely be able to respond to Washington's appeals for help until the NATO summit in April in France and Germany.
"I think we need to look to further weeks and the summit" to get further contributions, Appathurai said.
Before Thursday's start of the two-day conference, Gates said he had largely given up hope that NATO countries - many with strong anti-war constituencies at home - would be willing to commit more troops for the long-term to Afghanistan.
Instead, he told reporters that he would ask his counterparts for help to counter militants and improve security before national elections later this year, and for more nonmilitary assistance such as training Afghan police and counter-narcotics activities.
"I hope that it may be easier for our allies to do that than significant troop increases," Gates said.
NATO Secretary-General Jaap de Hoop Scheffer, who has been pushing for European nations to send more troops, delivered a bleak assessment of the war, acknowledging that the situation was not improving despite the influx of 13,000 additional NATO forces during the past year.
"We are frankly not where we had hoped to be," he said. "The south and east of Afghanistan are riven by insurgency, while drugs and the lack of effective government contribute to the frustration felt by Afghans at the lack of progress in building their country up."
Gates Critical Of Manas Air Base Decision
Kyrgyzstan's parliament voted Thursday to close the base that resupplies military operations in Afghanistan. If Kyrgyz President Kurmanbek Bakiyev signs the bill and an eviction notice follows, the United States will have 180 days to vacate the base.
Bakiyev unexpectedly called this month for the closure of the Manas base, a transit point for 15,000 troops and 500 tons of cargo each month to and from Afghanistan. Russia is widely assumed to be behind the decision, although Moscow denies it.
"I think that the Russians are trying to have it both ways with respect to Afghanistan in terms of Manas," Gates said, referring to the U.S. base in Kyrgyzstan, a former Soviet republic.
"On one hand you're making positive noises about working with us in Afghanistan and on the other hand you're working against us in terms of that airfield which is clearly important to us," Gates said.
But Appathurai played down the importance of the Manas base in supplying the forces in Afghanistan.
"There is plenty of flexibility in the logistical supply chain for NATO and for NATO allies," he said. "There are alternatives; they will be used. And allies will continue to supply their forces as needed."
Although Taliban militants have repeatedly attacked NATO's main logistics line through Pakistan, it remains open and accounts for 80 percent of the supplies used by the international forces, Appathurai said.
An alternate route through Russia also is under consideration.
Polish authorities deployed hundreds of troops and police to secure the meeting. But several hundred protesters rallied peacefully in Krakow's old city center to protest Poland's membership in NATO.
They carried banners reading: "We've already had Moscow, we don't want Washington."