sox returns an error when I try to handle mp3 files

Hello so below is the bargain, I used:

$ yum install sox 

To install it in CentOS 6. Afterwards I did a fast test:

$ sox test.mp3 test.amr

and also this is what it returns:

$ sox formats: no handler for file extension `mp3'

I require this performed with sox not lame due to the fact that I will certainly require to utilize it for blending and also various other features not readily available with lame.