port / portupgrade hangs

[Pieter Donche]

Sometimes (not often) when installing ports from the ports collection or
upgrading ports (via portupgrade -R) when fetching some needed tar.gz 
file, the fetch hangs, just like now:

=> rdiff-backup-1.2.6.tar.gz doesn't seem to exist in 
/usr/ports/distfiles/.
=> Attempting to fetch from 
http://download.savannah.gnu.org/releases/rdiff-backup/.
fetch: 
http://download.savannah.gnu.org/releases/rdiff-backup/rdiff-backup-1.2.6.tar.gz: 
Moved Temporarily
=> Attempting to fetch from 
http://ftp.cc.uoc.gr/mirrors/nongnu.org/rdiff-backup/.
rdiff-backup-1.2.6.tar.gz                      43% of  191 kB  107 kBps

This is now immobile for over an hour ...

Up to now when such a hang occured, I just waited and waited and 
eventually it would continue and finish the job.

But, is there a safe way to do a retry?
I dare not just do a Ctrl-C and issue
# portupgrade -R rdiff-backup
again, since I have no no clue what could go wrong if one does that ...

Or is it save to do Ctrl-C and try again?