  We consider six-dimensional supergravity with Abelian bulk flux compactified
on an orbifold. The effective low-energy action can be expressed in terms of
N=1 chiral moduli superfields with a gauged shift symmetry. The D-term
potential contains two Fayet-Iliopoulos terms which are induced by the flux and
by the Green-Schwarz term canceling the gauge anomalies, respectively. The
Green-Schwarz term also leads to a correction of the gauge kinetic function
which turns out to be crucial for the existence of Minkowski and de Sitter
vacua. Moduli stabilization is achieved by the interplay of the D-term and a
nonperturbative superpotential. Varying the gauge coupling and the
superpotential parameters, the scale of the extra dimensions can range from the
GUT scale down to the TeV scale. Supersymmetry is broken by F- and D-terms, and
the scale of gravitino, moduli, and modulini masses is determined by the size
of the compact dimensions.
