We report an improved measurements of direct CP violation in the decay B 0 → K + π − using 350 fb −1 of data and measurements of B meson decays to two kaons using 253 fb −1 of data. The measured CP violating asymmetries are A CP (K + π − ) = −0.113 ± 0.022(stat.) ± 0.008(syst.), where the latter correspond to the intervals −0.03 < A CP (K + π 0 ) < 0.11 and −0.12 < A CP (π + π 0 ) < 0.15 at 90% confidence level. We also find evidence for signals in B + → K 0 K + and B 0 → K 0 K 0 with

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... ces of 3.0σ and 3.5σ , respectively. (Charge-conjugate modes included) The corresponding branching fractions are measured to be B(B + → K 0 K + ) = (1.0 ± 0.4 ± 0.1) × 10 −6 and B(B 0 → K 0 K 0 ) = (0.8 ± 0.3 ± 0.1) × 10 −6 . No signal is observed in the decay B 0 → K + K − and we set an upper limit of 3.7 × 10 −7 at 90% confidence level. These results are obtained from a data sample collected near the ϒ(4S) resonance, with the Belle detector at the KEKB asymmetric energy e + e − collider.