WASHINGTON - The United States administration has confirmed that five Pakistanis were among the detainees at the notorious American prison in Guantanamo Bay as the Pakistan Embassy here stepped up efforts to secure their custody, an embassy spokesman said Sunday. These are: Aamaar Al-Baluchi, Majid Khan, Abdul Rabbani, Ahmed Ghulam Rabbani and Siafullah Piracha. One detainee Qari Muhammad Saad Iqbal was handed over to Pakistani interior ministry on August 29, as a result of these efforts, the spokesman said. Ambassador Husain Haqqani and the embassy officials have been meeting with the State Department and Pentagon officials, stressing that the cases against the Pakistanis should be pursued in Pakistan in the case of any incriminating evidence. The Pakistani elected government, sensitive to the public opinion on the issue of detention of Pakistanis in Guantanomo bay, has instructed the embassy to work on securing the early custody of the detainees, the spokesman said.   "In the light of these directives, the Pakistani diplomats led by the ambassador are making vigorous efforts to get their custody," he added.