Empty event_log file


I have a problem with logging the asterisk events.

I have the following entries in the logger.conf file:

in the [general] section:
event_log = yes

in the [logfiles] section (this I added today as an act of despair):
event_log => debug

The event logger is started:
Jan 16 15:38:18 VERBOSE[31419] logger.c: Asterisk Event Logger Started /var/log/asterisk/event_log

but the created file /var/log/asterisk/event_log is empty all the time.

Is there anything more that I should do to make it work?