Can Buddhism be fundamentalist?

Is it fundamentalism if Buddhists believe Buddha's path is the only path, and that all other spiritual traditions or sects are false? And if so, does it exist much in Buddhism? By fundamentalism, I mean a person believing that their path is the only path, for them and others who believe like them. I.e. can a Buddhist see another spiritual tradition as valid, even if it is not Buddhism? Such as an agnostic or a mystic from that tradition?