I'm not sure there is much more the pakistani Govt. can do. There is already a lot of hostility towards the Pakistani president and there have been several assassination attempts already. If he were to take serious action against these extremists it might be enough to result in the Govt. being overthrown and I'm sure that is the last thing anyone wants considering the govt. to replace the current one would be a radical one that would openly support terrorism and this would make Nuclear weapons easily available to any terrorist group.