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The normal-state in-plane resistivity below the zero-field superconducting transition temperature T_{c} and the upper critical field μ_{0}H_{c2}(T) was measured by suppressing superconductivity in pulsed magnetic fields for K_{0.70}Fe_{1.46}Se_{1.85}Te_{0.15}. The normal-state resistivity ρ_{ab} is found to increase logarithmically with decreasing temperature as (T/T_{c})→0. Similar to granular metals, our results suggest that a superconductor–insulator transition below zero-field T_{c} may be induced in high magnetic fields. This is related to the intrinsic real-space phase-separated states common to all inhomogeneous superconductors.