The Pakistan government received permission, from tribal chiefs in the area near Tora Bora, to move troops into the area. The "Northwest Tribal Areas" are not ruled by the Pakistan government, but by tribal leaders. The government has to negotiate for anything it wants to do in the area. Otherwise, the heavily armed tribesmen will resist violently. The tribes in the hills are the most resistant to government rule, while those on the plains to the east are more amenable to laws that affect all of Pakistan.