The leading nonperturbative QCD corrections to the perturbative potentials for the interactions between quarks and between a quark and an antiquark are obtained in the framework of the unitary expansion of the scattering operator. The contributions of the quark and gluon condensates (qq) and (GG) to the propagators as well as the vertices of the scattering matrix are included. Both cases of equal and different quark masses are investigated. The results show that there are linear terms with complicated structure and a cubic spin-independent term, the spin structure of which are vector-type. The exponential attenuation terms and the Yukawa terms appear automatically in the potentials.