U.S. Defense Secretary Chuck Hagel held three conversations with the head of Egypt's armed forces on Friday and Saturday, emphasizing the need for "a peaceful civilian transition in Egypt," the Pentagon said on Saturday.
A U.S. official, speaking on condition of anonymity, said the conversations between Hagel and General Abdel Fattah al-Sisi lasted more than two hours, showing the intensive contacts Washington is having with the military leader following last week's overthrow of President Mohamed Mursi.
"In their conversations, Secretary Hagel emphasized the need for a peaceful civilian transition in Egypt," Pentagon spokesman George Little said in a statement.
"He also noted the importance of security for the Egyptian people, Egypt's neighbors, and the region."
The Pentagon did not give details of Sisi's reaction.
The disclosure of these conversations came the same day President Barack Obama condemned the violence in Egypt and said that the United States was not aligned with any particular Egyptian political party or group.
Obama, who spent the weekend at the Camp David presidential retreat outside Washington, convened a conference call with members of his national security team to discuss the events in Egypt.
The Obama administration had grown skeptical of Mursi's ability to lead Egypt. While the United States has expressed concern about the military takeover, it has neither condemned it nor called it a coup, prompting speculation that the United States tacitly supports it.
A U.S. official, speaking on condition of anonymity, had previously told Reuters that Hagel had warned against a coup in a conversation he had with Sisi the day before the military overthrew Mursi.
Obama has ordered a review to determine whether annual U.S. assistance of $1.5 billion, most which goes to the Egyptian military, should be cut off as required by law if a country's military ousts a democratically elected leader.
The top U.S. military officer, General Martin Dempsey, has also spoken with his Egyptian counterpart since Mursi's overthrow.
No details on Dempsey's Thursday conversation with Lieutenant General Sedki Sobhi, chief of staff of Egypt's armed forces, were released. But Dempsey publicly warned that there would be consequences if Mursi's overthrow was viewed as a coup.
"There's laws that bind us on how we deal with these situations," Dempsey told CNN on Wednesday.