KABUL, Afghanistan  At least 100 relief workers in Afghanistan have been killed so far this year, far more than in any previous year, prompting a debate within humanitarian organizations about whether American military strategy is putting them and the Afghans they serve at unnecessary risk.

Most of the victims worked for aid contractors employed by NATO countries, with fewer victims among traditional nonprofit aid groups.

The difference in the body counts of the two groups is at the heart of a question troubling the aid community: Has American counterinsurgency strategy militarized the delivery of aid?

That doctrine calls for making civilian development aid a major adjunct to the military push. To do that there are Provincial Reconstruction Teams in 33 of 34 provinces, staffed by civilians from coalition countries to deliver aid projects. The effort is enormous, dominated by the Americans; the United States Agency for International Development alone is spending $4 billion this year, most of it through the teams.