sox returns an error when I try to handle mp3 files

Hello so here is the deal, I used: $ yum install sox To install it in CentOS 6. After that I did a quick test: $ sox test.mp3 test.amr and this is what it returns: $ sox formats: no handler for file extension `mp3' I need this done with sox not lame because I will need to use it for mixing and other functions not available with lame.