Mostow-Margulis rigidity with locally compact targets

Let Gamma be a lattice in a simple higher rank Lie group G. We describe all locally compact (not necessarily Lie) groups H in which Gamma call be embedded as a lattice. For lattices Gamma in rank one groups G (with the only exception of non-uniform lattices in G similar or equal to SL2(R), which are virtually free groups) we give a similar description of all possible locally compact groups H, in which Gamma can be embedded as a uniform lattice.