  The s-wave meson-baryon interaction is studied using the lowest-order chiral
Lagrangian in a unitary coupled-channels Bethe-Salpeter equation. In the
strangeness $S=-1$ sector the low-energy $K^- p$ dynamics leads to the
dynamical generation of the $\Lambda(1405)$ as a ${\bar K}N$ state, along with
a good description of the $K^- p$ scattering observables. At higher energies,
the $\Lambda(1670)$ is also found to be generated dynamically as a $K \Xi$
quasibound state for the first time. For strangeness S=0, it is the
$S_{11}(1535)$ resonance that emerges from the coupled-channels equations,
leading to a satisfactory description of meson-baryon scattering observables in
the energy region around the $S_{11}(1535)$. We speculate on the possible
dynamical generation of $\Xi$ resonances within the chiral $S=-2$ sector as
${\bar K} \Lambda$ or ${\bar K} \Sigma$ quasibound states.
