  We have obtained exact three dimensional BTZ type solutions with gauge
fields, for string theory on a gauge symmetric gravitational background
constructed from semi-simple extension of the Poincare algebra (and the Maxwell
algebra) in 2 + 1 dimensions. We have studied the models for two non-Abelian
and Abelian gauge fields solutions and shown that the related sigma models for
each of these backgrounds is a SL(2;R) WZW (Wess-Zumino-Witten) model and that
they are classically canonically equivalent. We have also obtained the dual
solution for the Abelian case and by interpreting the new field strength
tensors of the Abelian solution as electromagnetic field strength tensors shown
that dual models coincide with the charged black string solution.
