A theoretical description of long-range correlations between observables measured in separated rapidity intervals for nucleus–nucleus collisions at high energies is given. With allowance for an actual distribution of nucleons in nuclei, the pt-n and n-n correlation functions and respective correlation coefficients are calculated at various values of the impact parameter. It is shown that fluctuations of the impact parameter at a level of 1 fm, which are irremovable in experiments, affect the correlation coefficients substantially. It is shown that pt-n correlations become much more pronounced upon going over from the SPS to the RHIC and LHC energies. The pt-n and n-n correlation functions calculated for the minimumbias case (that is, without selection in centrality) are compared with experimental data on PbPb collisions at the SPS energies. © 2007 Pleiades Publishing, Ltd.