  We construct a generalization of the two-dimensional Wess-Zumino-Witten model
on a $2n$-dimensional K\"ahler manifold as a group-valued non-linear sigma
model with an anomaly term containing the K\"ahler form. The model is shown to
have an infinite-dimensional symmetry which generates an $n$-toroidal Lie
algebra. The classical equation of motion turns out to be the
Donaldson-Uhlenbeck-Yau equation, which is a $2n$-dimensional generalization of
the self-dual Yang-Mills equation.
