VSFTPD - problem with chroot environment

I have FTP and SFTP (Openssh 5.3) server running in my centos 5.5

Jail environment for FTP and SFTP users are at different locations as /FTP and /jailed

I successfull created a chroot environment for both my ftp and sftp users . All the ftp users are jailed in their particular directory.

Problem - I tried loging to the FTP server using sftp command and credentials of ftp user and I was able to come of the jail environment and could access all other directories.

For example - $> ftp ftp.server.name

username - abc

pass - ######

(Now user "abc" is stuck in his own directory)

While user "abc" can come out of its jail environment using sftp

$> sftp ftp.Server.Name

username - abc

pass -###

How should I solve this ?