How do I sample a synthetic random field at specified points?

Hail, all.

I have been able to generate a 3D synthetic random field (via unconditional
Gaussian simulation) using gstat package. I now need to sample the fields
at some specified coordinate points (not random points). I have not been
able to find a function to do this. Kindly note that my specified sample
points also come in 3D as I would need to sample at multiple depths for
each x-y coordinates.

Thank you, all.

Olatunde