On Tuesday, Defense Secretary Leon Panetta stepped up the effort to get the Pakistani government to crack down on Haqqani network, saying, "Our biggest concern right now is to put as much pressure as possible on the Pakistanis to exercise control from their side of the border. We've continued to state that this cannot happen. We cannot have the Haqqanis coming across the border attacking our forces, attacking (Afghans), and then disappearing back into a safe haven. That is not tolerable and we have urged them to take steps."