  B.\,Ya.\,Levin has proved that zero set of a sine type function can be
presented as a union of a finite number of separated sets, that is an important
result in the theory of exponential Riesz bases. In the present paper we extend
Levin's result to a more general class of entire functions $F(z)$ with zeros in
a strip $0<q \leq \Im z \leq Q,$ such that $|F(x)|^2$ satisfies the
Helson--Szeg\"o condition. Moreover, we demonstrate that instead of the last
condition one can require that $\log|F(x)|$ belongs to the BMO class.
