We report a study of the suppressed decays B- -> [K(+)pi(-)](D)K- and B- -> [K+ pi(-)](D)pi(-), where [K+ pi(-)](D) indicates that the K(+)pi(-) pair originates from a neutral D meson. These decay modes are sensitive to the unitarity triangle angle phi(3). We use a data sample containing 275x10(6) B (B) over bar pairs recorded at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric e(+)e(-) storage ring. The signal for B- -> [K+ pi(-)](D)K- is not statistically significant, and we set a limit r(B) (D) over bar K-0(-))/A(B- -> (DK-)-K-0)vertical bar. We observe a signal with 6.4 sigma statistical significance in the related mode, B- -> [K(+)pi(-)](D)pi(-)
