  Possible bound and resonant states of the hypernuclear systems $\Lambda nn$
and $\Lambda\Lambda n$ are sought as zeros of the corresponding three-body Jost
functions calculated within the framework of the hyperspherical approach with
local two-body S-wave potentials describing the $nn$, $\Lambda n$, and
$\Lambda\Lambda$ interactions. Very wide near-threshold resonances are found
for both three-body systems. The positions of these resonances turned out to be
sensitive to the choice of the $\Lambda n$-potential. Bound $\Lambda nn$ and
$\Lambda\Lambda n$ states only appear if the two-body potentials are multiplied
by a factor of $\sim 1.5$.
