  We study superconductivity suppression due to thermal fluctuations in
disordered wires using the replica nonlinear $\sigma$-model ($NL\sigma M$). We
show that in addition to the thermal phase slips there is another type of
fluctuations that result in a finite resistivity. These fluctuations are
described by saddle points in $NL\sigma M$ and cannot be treated within the
Ginzburg-Landau approach. The contribution of such fluctuations to the wire
resistivity is evaluated with exponential accuracy. The magnetoresistance
associated with this contribution is negative.
