Does every proper algebraic space (over a field, say) admit a closed immersion into a smooth proper algebraic space?

Remark: Of course, if we say "projective" instead of "proper" then the answer is tautologically "yes": we can take the ambient variety to be some projective n-space. But I'm curious about the general case.

algebraic space? It seems to me that this argument only works if $X$ is ascheme, or I am missing something? $\endgroup$ – Francesco Polizzi Nov 7 '14 at 15:12