If you choose to run CLI commands in the background via the standard SSH interface, it is possible that keyboard breaks interrupt running processes. This is a standard behaviour if the TTY setting has been set to sane, and is remedied by providing the SSH command with the -n option to automatically send keyboard input to /dev/null. This type of command can only be used with key-based authentication, since at the point that it is run, the command is run in the background so you can no longer interact with it.

$ ssh -l admin localhost -p 10000 -n "importAssembly Repository name=MyRepository
url=http://example.com/myassembly.ova" &

Note that using the -n flag does not make sense if you intend to maintain an interactive session within the CLI.