But neither officer has governed, and both are considered fierce protectors of the status quo.
U.S. officials say Enan is believed to be more willing to maintain close ties to the U.S. He was in Washington for a week of Pentagon meetings when the Cairo protests erupted Jan. 25.
Enan rushed home but has kept in touch with Adm. Michael G. Mullen, chairman of the U.S. Joint Chiefs of Staff. The two last spoke by phone Thursday when Mubarak appeared intent on clinging to power, said a spokesman for Mullen.
Tantawi is the head of the military council. He spoke by phone Saturday with U.S. Defense Secretary Robert M. Gates, the Pentagon said. Tantawi also spoke with Ehud Barak, the Israeli defense minister, according to Israel's Channel 1.
The conversation with Gates was the two men's sixth since the crisis began, said Pentagon spokesman Geoff Morrell. He declined to provide details of it.
U.S. officials said Tantawi played a major role in the decision to oust Mubarak, though the details were still unclear. Elliott Abrams, deputy national security advisor to former President George W. Bush, said that Tantawi has over the years resisted U.S. military officials' efforts to build personal relationships.
Washington has had far closer relations with former intelligence chief Omar Suleiman, whom Mubarak appointed vice president during the crisis. His role apparently has now been eclipsed by the army.
U.S. officials were scrambling to adjust to the changes. The Pentagon brass who deal with Tantawi and Enan don't normally follow the intricacies of Egypt's internal politics.
"We are used to talking to them about Iran, about aid, the peace process, counter-terrorism and other strategic issues, not whether or not to lift the emergency powers law," said a U.S. national security official who spoke on condition of anonymity.
The official said Egypt was well represented by U.S. lobbyists in Washington, a channel that the Obama administration might turn to for sending delicate political messages to the country's new leadership.
U.S. officials say the Egyptian military is avidly interested in ensuring no reduction in the aid Egypt has gotten from the United States since it signed the peace treaty with Israel, and has fought any effort in Congress to withhold the money or place conditions on it.
Egyptian officers share U.S. concern about Iran's rising power in the region. Although Washington is largely focused on Iran's nuclear program, Egypt's military is more worried about its funding of Islamist groups and militias in the region, including Hezbollah and Hamas, U.S. officials say.
Israel has worked closely with Egypt's military to battle Islamic extremists, particularly in the Gaza Strip and Egypt's Sinai peninsula. But some Israeli officers are highly critical of Egypt's failure to halt weapons flowing into Gaza through smuggling tunnels.
Despite the problems, Israeli officials believe they can trust the new Egyptian rulers.
Defense analyst Ron Ben-Yishai told Israel Radio that Egypt's military "now has a country to run. It does not need a war with Israel. This was against its interests before, and even more so now."
Times staff writers Edmund Sanders in Jerusalem and Paul Richter in Washington and Amro Hassan of The Times' Cairo Bureau contributed to this report.