We consider a microscopic model of itinerant electrons coupled via ferromagnetic exchange to a local magnetization whose direction vector n͑r , t͒ varies in space and time. We assume that to first order in the spatial gradients and time derivative of n͑r , t͒, the magnetization distribution function f͑p , r , t͒ of itinerant electrons with momentum p at position r and time t has the ansatz form f͑p , r , t͒ = f ʈ ͑p͒n͑r , t͒ + f 1r ͑p͒n ϫ ٌ r n + f 2r ͑pٌ͒ r n + f 1t ͑p͒n ϫ ץ t n + f 2t ͑p͒ץ t n. Using the Landau-Sillin equations of motion approach ͑Zh. Eksp. Teor. Fiz. 33, 1227 ͑1957͒ ͓Sov. Phys. JETP 6, 945 ͑1958͔͒͒, we derive explicit forms for the components f ʈ ͑p͒, f 1r ͑p͒, f 2r ͑p͒, f 1t ͑p͒, and f 2t ͑p͒ in "equilibrium" and in out-of-equilibrium situations for ͑i͒ no scattering by impurities, ͑ii͒ spin-conserving scattering, and ͑iii͒ spin-nonconserving scattering. The back action on the localized electron magnetization from the out-of-equilibrium part of the two components f 1r and f 2r constitutes the two spin transfer torque terms.