Is the American war on Afghanistan clashing with the relevancy of the international humanitarian law?

The main aim of international humanitarian law is to minimize unnecessary suffering by regulating the conduct of hostilities and the treatment of persons in the power of the enemy.
The essential humanitarian function of humanitarian law is carried out through the parties to the conflict. They have rights and responsibilities. There can be no humanitarian law conflict without identifiable parties. “Terror” or “terrorism” cannot be a party to the conflict. As a result, a war on terror cannot be a humanitarian law event. This does not, of course, mean that humanitarian law cannot apply to the conduct of persons responsible for the September 11 attacks, it would just not consider it as an armed conflict; so the rules and treatments that is happening in Afghanistan with the civilians there is in no way justified by humanitarian law because, the operations are not held according to their laws and America is carrying the operations and treatment by their own customary law.
In our age as it has in the previous ones, Humanitarian law suffices as a basis to run a world in an orderly fashion. Its boundaries are properly drawn in a respectful balance among interests of state security, individual security, and civil liberties. But it is only effective when properly implemented. It’s very vitality and relevance in the War on Terror stems not from any claim that it is capable of encompassing all of the exigencies of terrorism and the efforts to combat it. The strength of humanitarian law lies, rather, in the fact that it is adequate to deal with such exigencies when they amount to armed conflict.

Reference:
Interesting Times for
International Humanitarian
Law: Challenges from the
“War on Terror”
Gabor Rona
Article published in "the Fletcher Forum of World Affairs", vol. 27:2, Summer/Fall 2003