Complete integrable systems with unconfined singularities

We prove that any globally periodic rational discrete system in K^k(where K denotes either R or C), has unconfined singularities, zero algebraic entropy and it is complete integrable (that is, it has as many functionally independent first integrals as the dimension of the phase space). In fact, for some of these systems the unconfined singularities are the key to obtain first integrals using the Darboux-type method of integrability.