  We show that the minimal supergravity extension of the standard model
automatically contains topologically stable electroweak strings if the hidden
sector is invariant under the exact R-symmetry. These defects appear in the
form of the semiglobal R-strings, which necessarily carry $Z$-flux inside their
core. This result is independent from the particular structure of the hidden
sector. Discussed strings differ fundamentally from the embedded $Z$-strings.
If R-symmetry is explicitly broken (e.g. due to an anomaly), the decay of the
semiglobal strings may have important implications for the baryogenesis.
