The geometric approach to the control of internal forces for robotic grasping is explored. Since the manipulation of deformable objects is a frequently occurrence (medical applications, manipulation of rubber and plastic in industry), manipulation systems with significant contact elasticity are studied. The presence of non-negligible compliance at the contacts, implies that the object dynamics cannot be neglected when attempting to control internal forces without affecting the object position. A geometric approach to derive a control law decoupling the internal force control action from the object dynamics is proposed.