Exact quantum-electrodynamic calculations of the interelectron interaction corrections are performed for the 1s_1/22s_1/2 ¹S₀, 1s_1/22p_1/2 ³P ₀, and 1s_1/22s_1/2 ³S₁ configurations in He-like ions and for the (1s_1/2)²2s _1/2 and (1s_1/2)²2p_1/2 configurations in Li-like ions for all charges of nuclei 10 ≤ Z ≤ 92. The calculations are performed in the Coulomb calibration. The Coulomb-Coulomb and the Coulomb-Breit parts are calculated exactly, and the Breit-Breit part of the correction is calculated by neglecting the retardation. The calculations are the most exact of those available by now.