  We present results of phase- and time-resolved study of iron spectral
features in the emission of the Be/X-ray transient pulsar V0332+53, during its
type II outburst in 2004 using archival RXTE/PCA data. Coherent pulsations of
both fluorescent iron line at {\approx}6.4 keV and neutral iron K-edge at
{\approx}7.1 keV have been detected throughout the entire outburst. The
pulsating iron K-edge is reported for the first time for this object. Near the
peak of the outburst, the 3-12 keV pulse profile shows two deep, F_max / F_min
~ 2, and narrow dips of nearly identical shape, separated by exactly
{\Delta}{\phi}=0.5 in phase. The dip spectra are nearly identical to each other
and very similar in shape to the spectra outside the dips. The iron K-edge
peaks at the phase intervals corresponding to the dips, although its optical
depth {\tau}_K ~ 0.05 is by far insufficient to explain the dips. The iron line
shows pulsations with a complex pulse profile without any obvious correlation
with the total flux or optical depth of the K-edge. Accounting for the
component associated with reprocessing of the pulsar emission by the surface of
the donor star and circumstellar material, we find a very high pulsation
amplitude of the iron line flux, F_max / F_min ~ 10. We demonstrate that these
properties of V0332+53 can not be explained by contemporary emission models for
accreting X-ray pulsars and speculate about the origin of the observed iron
spectral features.
