openssh unix dev - Jun 2010 - disable sftp log

Hi, 

I need to disable the messages of the sftp while connecting or fetching or
anything but the errors.

When I type sftp user at server > $logfile
all the messages are written inthe $logfile

but I need that only the errors be written there.

Now it shows:
connecting to "server"
fetching /path/file to /path2/file


how can I avoid this?

thanks in advance.
Dany