  We present the results of the monitoring programmes performed with the
Swift/XRT telescope and aimed specifically to detect an abrupt decrease of the
observed flux associated with a transition to the propeller regime in two well
known X-ray pulsars 4U 0115+63 and V 0332+53 during their giant outbursts in
2015. Such transitions were detected at the threshold luminosities of
$(1.4\pm0.4)\times10^{36}$ erg s$^{-1}$ and $(2.0\pm0.4)\times10^{36}$ erg
s$^{-1}$ for 4U 0115+63 and V 0332+53, respectively. Spectra of the sources are
shown to be significantly softer during the low state. In both sources, the
accretion at rates close to the aforementioned threshold values briefly resumes
during the periastron passage following the transition into propeller regime.
The strength of the dipole component of the magnetic field required to inhibit
the accretion agrees well with estimates based on the position of the cyclotron
lines in their spectra, thus excluding presence of a strong multipole component
of the magnetic field in the vicinity of the neutron star.
