A top US State Department official warned Friday that NATO's future may hinge on alliance members dropping conditions they have placed on their troops' service in Afghanistan. Undersecretary of State for Political Affairs Nicholas Burns says the so-called "caveats" on what various contingents may do in that country are an "existential" issue for NATO. VOA's David Gollust reports from the State Department.

The Bush administration has made clear its irritation over conditions some NATO countries have placed on their soldiers' activity in Afghanistan.

But the remarks by Undersecretary Burns were the most pointed to date, with Burns suggesting that the future of the alliance itself may be jeopardized if there are not uniform rules of engagement for all allied troops in Afghanistan.

"We feel this is an existential issue for NATO," he said. "And I mean it quite sincerely, an existential issue. NATO is all about collective work together, solidarity, and when you have 26 allies in Afghanistan, and you have four countries doing a majority of the fighting - Canada, the Netherlands, the United Kingdom and the United States - it is right for us to ask the other allies to make a greater effort, to remove the military restrictions so that everybody can be called upon to make the kind of sacrifices that need to be made."

Burns spoke to reporters here after Secretary of State Condoleezza Rice, at a meeting of the 26 NATO foreign ministers in Brussels, appealed to the allies to intensify their Afghan efforts.

Rice outlined Bush administration plans to seek more than $10 billion in additional aid for the Afghan government of President Hamid Karzai, amid an expectation that resurgent Taleban forces will mount a spring offensive in the coming months.

The secretary of state told her colleagues that every NATO member state must take a hard look at what more can be done to help the Afghan people, and to support one another.

Burns said here that some NATO countries had committed in Brussels to drop their caveats, while he said other governments, including Germany, must operate under deployment conditions imposed by their parliaments.

There are about 34,000 NATO troops in Afghanistan, including some 12,000 U.S. soldiers. Another 12,000 American troops are there under direct U.S. command.

The new U.S. defense secretary, Robert Gates, who made his first visit to Afghanistan last week, has extended the tours of duty there for about 3,500 elite U.S. Army troops by four months, this intended in part as an example for other NATO partners.

He told Pentagon reporters Friday that if there is a spring offensive in Afghanistan, it should be by the Western allies and the Afghan government:

"I would say I came back from Afghanistan more optimistic than when I went there," he said. "And I think what our commanders see this spring is an opportunity to make the spring offensive our offensive, and to pre-empt whatever plans the Taleban may have."

Gates said if things go as anticipated, it will not be necessary to further extend the tours of U.S. troops.

He has said in recent days that he would be receptive to increasing the overall U.S. troop presence in Afghanistan if that is the recommendation of field commanders