  We report the discovery of low-frequency quasi-periodic oscillations (QPOs)
in the power spectrum of the X-ray nova MAXI J1535-571 at the initial stage of
its outburst in September 2017. Based on data from the SWIFT and INTEGRAL
instruments, we have traced the evolution of the QPO parameters (primarily
their frequency) with time and their correlation with changes in the X-ray
spectrum of the source (changes in the emission flux and hardness). We place
constraints on the theoretical QPO generation models.
