WASHINGTON — The Pentagon said Saturday that four Afghans from the Guantanamo Bay detention center have been returned to their home country in what U.S. officials are citing as a sign of their confidence in new Afghan President Ashraf Ghani. Obama administration officials said they worked quickly to fulfill the request from Ghani, in office just three months, to return the four – long cleared for release – as a kind of reconciliation and mark of improved U.S.-Afghan relations. There is no requirement that the Afghan government further detain the men, identified as Mohammed Zahir, Shawali Khan, Abdul Ghani and Khi Ali Gul.