In his talks over the phone with his Egyptian counterpart General Abdel-Fattah al-Sisi, the Pentagon chief discussed "the importance of the constitutional referendum for Egypt's overall political transition," Pentagon spokesman John Kirby said in a readout of the conversation.

　　Hagel "stressed the importance of a transparent referendum in which all Egyptians have the opportunity to cast their vote freely, " and urged al-Sisi to ensure the international and domestic observers have "full access," Kirby said.

　　Egypt has been hit with waves after waves of protests and a deteriorating security situation since Mohamed Morsi, the country' s first elected president, was ousted by the military in early July, 2013.

　　Last month, the interim government declared the Muslim Brotherhood, to which Morsi belongs, a "terrorist group".