Bitbake: How to only fetch the sources?

There is a project in which we use project yocto, and our metas fetch source from some remote git repositories.

The problem is that these repositories are only accessible in some particular situations/specific times.

Therefore, I need a way to fetch the repos (when they are available), as to have them locally, but not build anything at that time.

Is this possible?

Solution

Starting from Yocto 2.5, it has changed:

 bitbake <target> --runall=fetch

Previously it was:

bitbake <target> -c fetchall