Electromagnetic radiation produces frame dragging

It is shown that for a generic electrovacuum spacetime, electromagnetic radiation produces vorticity of worldlines of observers in a Bondi–Sachs frame. Such an effect (and the ensuing gyroscope precession with respect to the lattice) which is a reminiscence of generation of vorticity by gravitational radiation, may be linked to the nonvanishing of components of the Poynting and the super–Poynting vectors on the planes othogonal to the vorticity vector. The possible observational relevance of such an effect is commented.