The United States put pressure on embattled Egyptian President Mohammed Morsi on Tuesday to listen to concerns of huge anti-government protests, as Egypt's army planned to push the Islamist leader aside if he fails to strike a power-sharing deal with his opponents within 24 hours.

In a phone call at the end of an African tour, President Barack Obama told Morsi that the political crisis can only be resolved by talking with his opponents.

"President Obama encouraged President Morsi to take steps to show that he is responsive to their concerns, and underscored that the current crisis can only be resolved through a political process," the White House said in a statement.

Obama urged Morsi to create an inclusive political process. "Democracy is about more than elections," the statement said. "It is also about ensuring that the voices of all Egyptians are heard and represented by their government, including the many Egyptians demonstrating throughout the country."

Secretary of State John Kerry also called Egypt's foreign minister Mohamed Kamel Amr, the U.S. State Department said. "He conveyed the same message that the president conveyed to his counterpart, which is that it's important to listen to the Egyptian people," State Department spokeswoman Jen Psaki said.

State news agency MENA reported early on Tuesday that Amr tendered his resignation. It was unclear if he was still in his position when Kerry spoke to him. "I would refer you to the Egyptian government for his exact status," Psaki said when asked about Amr.

She said a media report that Washington had urged Morsi to hold early elections to end the crisis was inaccurate. The United States played a vital role in Egypt's transition to democracy when it withdrew support for strongman President Hosni Mubarak in 2011 in the face of mass protests in Egypt.

It has so far stayed away from the crisis enveloping Morsi's government, but the calls by Obama and Kerry were a clear sign that Washington wants to push Morsi toward dialogue with the opposition.

Egypt's army has plans to push Morsi aside and suspend the constitution if he fails to strike a power-sharing deal with his opponents within one day, military sources told Reuters in Egypt on Tuesday.

The United States is a big aid donor to Egypt and its military. Obama "told President Morsi that the United States is committed to the democratic process in Egypt and does not support any single party or group," the White House said.

Morsi, Egypt's first freely elected leader, was still clinging to power with tens of thousands of people on the streets from rival factions. There were some clashes between Morsi's Islamist supporters and those who want him forced out after only a year in office.

Meanwhile, the Foreign Ministry is not allowing the staff of the Israeli Embassy in Cairo to return to Egypt because of the tension and unrest there. Ministry officials said the diplomats will remain in Israel until the security situation improves.
Since the September 2011 attack on the embassy in Cairo, Israeli diplomatic activity there has been scaled back considerably.

The embassy building was abandoned after the attack and because of disputes between the Shin Bet security service, the Foreign Ministry in Jerusalem and the Egyptian Foreign Ministry, a suitable alternative structure has not been found. Lacking a functioning embassy, Israeli Ambassador Yaakov Amitai, attache Ariel Shafransky and other diplomats have been operating from a temporary location.

In advance of the mass demonstrations against Morsi scheduled for this past Sunday, the Foreign Ministry held consultations over possible security threats to the Israeli diplomats and decided not to let them return to Egypt, following their weekend off in Israel. A Foreign Ministry official said that under the prevailing circumstances, the diplomats would have had to remain confined to their homes in any case, severely limiting their ability to function.

The decision was not exceptional. Several times over the last year, the diplomats have been held back in Israel either because of demonstrations or diplomatic tensions. In some instances, they were recalled earlier in the week than usual.