No command found at Asterisk console

I tried to dial an internal extension from Asterisk console and get no command found error. Please advice.

[root@localhost ~]# asterisk -r
Asterisk CVS-Nv1-2-0-03/15/06-23:15:06, Copyright © 1999 - 2005 Digium.
Written by Mark Spencer

Connected to Asterisk CVS-Nv1-2-0-03/15/06-23:15:06 currently running on localhost (pid = 2653)
localhostCLI> dial 72001
No such command ‘dial’ (type ‘help’ for help)