ABSTRACT We study multidimensional generalisations of the classical Wiener-Hopf operators interpreting them as pseudo-differential operators with symbols having jump discontinuities on some surfaces in R^d, d\ge 1. The main objective is to justify a two-term quasi-classical asymptotic formula for the trace tr(g(T)) where T is the operator at hand, and g is some function. For smooth discontinuity surfaces and smooth functions g the sought formula was proved by A. Sobolev in 2009. The aim of this talk is to extend this result to piece-wise smooth surfaces, and to non-smooth functions g. These generalizations are of interest in Mathematical Physics and Quantum Information Theory. A part of this work was done in collaboration with H. Leschke and W. Spitzer.