[en] Using the light-front hamiltonian with two-body forces a consistent set of three-dimensional two- and three-body relativistic equations is derived. The structure of two-body equations is fixed by the restrictions imposed on the pairing interaction operator to be dependent only on internal variables and to satisfy the angular condition. It is shown that imposing the separability and angular conditions allows one to uniquely express the three-body mass operator through the two-body mass operators. The kernel of the equation for two-body scattering amplitude in three-body space is uniquely related to the two-body interaction operator but is not equal to the latter identically. The hamiltonian formalism developed in this paper to consider the systems with a fixed number of particles in relativistic range can be applied for the description of relativistic effects in nuclei