[en] We obtain a cluster expression for the two-time retarded Green's functions and the thermodynamic potential of a disordered crystal taking the electron-phonon and electron-electron interactions into account. The electron states of the system are described in the framework of a multiband tight-binding model. The calculations are based on the diagram techniques for temperature Green's functions. It is shown that the contributions of the scattering processes by clusters decrease with increasing the number of atoms in the cluster on some small parameter. The equation for the parameters of interatomic correlations (short-range and long-range orders) is obtained. The possibility of application of the obtained results to the investigation of the influence of strong electronic correlations on the electronic structure and properties of alloys of transition metals with narrow energy bands is shown