  Tensor operators associated with a given quantum Lie algebra admit a natural
description in the R-matrix language. Here we employ the R-matrix approach to
discuss the problem of fusion of tensor operators. The most interesting case is
provided by the quantum WZNW model, where, by construction, we deal with sets
of linearly independent tensor operators. In this case the fusion problem is
equivalent to construction of an analogue F(p) of the twisting element F which
is employed in Drinfeld's description of quasi-Hopf algebras. We discuss the
construction of the twisting element F(p) in a general situation and give
illustrating calculations for the case of the fundamental representation of
U_q(sl(2)).
