  A recent discovery of the periodic activity of the repeating fast radio burst
source FRB 180916.J0158+65 in the Canadian Hydrogen Intensity Mapping
Experiment (CHIME) hints at possible origin of the FRB from a freely precessing
neutron star with a magnetar magnetic field of about $10^{16}$ G. However, the
absence of simultaneously detected high-energy emission in the Swift and AGILE
observations imposes stringent constraints on the field magnitude and questions
the possibility of such a progenitor. We show that consideration of forced
precession of a neutron star does not encounter the difficulty. This kind of
precession takes place even if the neutron star is not deformed and is brought
about by the anomalous moment of electromagnetic forces induced by stellar
rotation and determined by non-corotational currents. Contrary to what is
expected for the currents of corotation, the anomalous torque calculated by the
direct method appears to be non-zero. If the observed 16.35-day period
corresponds to the period of stellar precession, the inferred internal magnetic
field appears to be about $6\times10^{14}$ G for rotational period 1 s. For
another possibly periodic FRB 121102 with 157-day period the magnetic field is
even lower, $2\times10^{14}$ G, thereby justifying earlier considerations and
not ruling out the hypothesis of FRB origin from precessing neutron stars.
