Given finitely many elements of a semi-simple Lie group $G$ of non compact type, I give a sufficient criterion so that they span an Anosov group (in particular discrete and word hyperbolic). The criterion is based on the action on the symmetric space $G/K$. As an application, I discuss the algorithmic recognizability of Anosov groups. This is joint work with M. Kapovich and B. Leeb.