In the present paper some :Newton-like iteration methods are developed to enclose solutions of nonlinear operator equations of the kind F(x) ~ O. Here F maps a certain subset of a partially ordered vector space into another partially ordered vector space. The obtained results are proved without any special properties of the orderings by taking use of a new kind of a generalized divided difference operator, so that they even hold for nonconvex operators. Furthermore a method for constructing including starting points is presented and two examples are given.