Accurate QED evaluations of the interelectron interaction for low lying two- and three-electron configurations for ions with nuclear charge numbers 60 less than or equal to Z less than or equal to 93 are presented. The three-photon interaction is also partly taken into account. The results are compared with available experimental data and with different calculations. A detailed investigation of the behaviour of the energy levels of the configurations 1s(1)/2s(1/2) S-1(0), 1s(1)/2p(1/2) P-3(0) near the crossing points Z = 64 and Z = 92 is carried out. The determination of the crossing points is important for the future experimental search for parity non-conserving effects in highly charged ions. (C) 2003 Elsevier Science B.V. All rights reserved.