ISLAMABAD - On the directions of Pakistan Telecommunication Authority (PTA), the cellular mobile operators have extended free calling facility on their own network to users with zero balance, stranded in Murree and Galliat areas.  “In view of an emergency situation in Murree and Galliat areas, the mobile phone users, currently present in these areas with no balance, have immediately been provided with free on-net calling facility,” said a PTA in a statement issued here on Sunday. The users had been asked to contact their concerned operators for more information. Moreover, PTA has also directed all telecom operators to ensure uninterrupted services to users and keep enough backup arrangements in case of power outages.