5f(N) --> 5f(N-1)6d(1) absorption spectra of U4+- and U3+-doped CS2NaYCl6, CS2LiYCl6, CS2NaYBr6, CsCdBr3, and Cs3Lu2Cl9 single crystals were recorded at 4.2 K in the 14 000-50 000 cm(-1) spectral range. The 5f(2) --> 5f(1)6d(1) absorption bands of U4+ ions were observed in the 30 000-37 000 cm(-1) energy range, and have been assigned as transitions from the H-3(4) ground multiplet of the 5f(2) configuration to crystal-field levels of the 5f(1)6d(t(2g))(1) manifold. The energies of the lowest levels of the 5f(1)6d(t(2g))(1) configuration have been for the first time determined for U4+ ions doped in a chloride or bromide host crystal. They are equal to 26 360 and 28 590 cm(-1) for U4+:CsCdBr3 and U4+ :Cs2NaYBr6 respectively and range from 30 360 to 31010 cm(-1) for U4+. doped in the chloride hosts. Highly structured vibronic bands of 5f(3) --> 5f(2)6d(t(2g))(1) absorption transitions of the U3+ ions appeared at an energy as low as 14 158 cm(-1), and have been assigned to transitions from the I-4(9/2) ground multiplet of the 5f(3) configuration to crystal-field levels arising from the configurations 5f(2)(H-3(4))6d(t(2g))(1)(Gamma(8g)) (barycenter at similar to16 000 cm(-1)) and 5f(2)(H-3(4))6d(t(2g))(1)(Gamma(7g)) (barycenter at similar to19 000 cm(-1)). Besides, some low intensity bands observed at similar to18 600 and above 21 000 cm(-1) have been assigned as transitions to the 5f(2)(F-3(2))6d(t(2g))(1)(Gamma(8g)) and 5f(2)(F-3(2))6d(t(2g))(1)(Gamma(7g)) levels, respectively. Transitions to the 5f(2)6d(e(g))(1) levels of U3+. ions have been observed as broad and unstructured bands at wavenumbers higher than 38 000 cm(-1). The crystal field splitting (10Dq) of the 5f(2)6d(1) configuration for U3+ doped in Cs2NaYCl6 single crystals amounts to similar to23 000 cm(-1), and the separation between Gamma(8g) and Gamma(7g) components of the t(2g) state, resulting from spin-orbit interaction for the 6d electron, can be evaluated as 3350 cm(-1). The splitting of the 5f(2)(L-2S+1(J))6d(gamma)(1)(Gamma(ig)) (gamma = t(2g) or eg; i = 7 or 8) configurations, resulting from the coupling of the 5f(2) core electrons with the 6d electron is somewhat smaller and amounts to similar to3000 cm(-1). The main feature of the crystal level structure observed in the 5f(3)-5f(2)6d(1) absorption spectra of U3+ ions reflects the dominating influence of the crystal field splitting and spin-orbit coupling of the 6d electron.