  We investigate low-temperature transport properties of thin TiN
superconducting films in the vicinity of the disorder-driven
superconductor-insulator transition. In a zero magnetic field, we find an
extremely sharp separation between superconducting and insulating phases,
evidencing a direct superconductor-insulator transition without an intermediate
metallic phase. At moderate temperatures, in the insulating films we reveal
thermally activated conductivity with the magnetic field-dependent activation
energy. At very low temperatures, we observe a zero-conductivity state, which
is destroyed at some depinning threshold voltage V_T. These findings indicate
formation of a distinct collective state of the localized Cooper pairs in the
critical region at both sides of the transition.
