  SWIFT J1756.9-2508 is one of the few accreting millisecond pulsars (AMPs)
discovered to date. We report here the results of our analysis of its aperiodic
X-ray variability, as measured with the Rossi X-ray Timing Explorer during the
2007 outburst of the source. We detect strong (~35%) flat-topped broadband
noise throughout the outburst with low characteristic frequencies (~0.1 Hz).
This makes SWIFT J1756.9-2508 similar to the rest of AMPs and to other low
luminosity accreting neutron stars when they are in their hard states, and
enables us to classify this AMP as an atoll source in the extreme island state.
We also find a hard tail in its energy spectrum extending up to 100 keV, fully
consistent with such source and state classification.
