U.S. Defense Secretary Chuck Hagel spoke to his Egyptian counterpart and army chief Abdel Fattah al-Sisi on Friday and Saturday, stressing the need for "a peaceful civilian transition" in the most populous Arab nation, the Pentagon said on Saturday.

In their phone conversation on three occasions, Hagel discussed with al-Sisi the ongoing events in Egypt and "emphasized the need for a peaceful civilian transition" in Egypt, Pentagon spokesman George Little said in a statement.

Al-Sisi announced on Wednesday the sacking of Mohamed Morsi as demonstrations by Morsi's opponents and supporters had roiled the country for days, and put the head of the Supreme Constitutional Court in charge of the country for a transitional period till fresh presidential and parliamentary elections are called.

In his talks with al-Sisi, Hagel "also noted the importance of security for the Egyptian people, Egypt's neighbors and the region," Little said.

Some 1.3 billion U.S. dollars in Washington's annual aid of 1.55 billion dollars go to the Egyptian military, but President Barack Obama has ordered a review of the assistance following the latest developments in Egypt.

For the past two days, U.S. Secretary of State John Kerry has also spoken about the situation in Egypt with his counterparts from Qatar, the United Arab Emirates, Saudi Arabia and Turkey as well as with the Omani Sultan Qaboos Bin Said and Mohamed ElBaradei, an opposition leader in Egypt, the State Department said on Saturday.