  Recently it is found that Weyl anomaly leads to new anomalous currents in an
external electromagnetic field in the curved spacetime. For simplicity, the
initial works mainly focus on weak gravitational fields and the anomalous
current is obtained for conformally flat spaces with small scale factors. In
this paper, we generalize the results to the case with arbitrary scale factors.
Firstly, we derive the transformation law of current under Weyl transformation,
from which one can read off the anomalous current in general conformally flat
spaces. Secondly, by using the Weyl transformation of currents we provide a new
derivation of the Weyl-anomaly-induced current near the boundary. Thus we have
obtained the two kinds of anomalous currents in the literature from a unified
formula. Finally, we extend the discussions to n-form fields and find similar
anomalous currents.
