Egypt's state news agency MENA says the military has a draft plan to suspend the constitution and set up an interim administration to lead the country to a new presidential election if President Muhammad Morsi fails to reach a solution with his opponents.
The army has set a deadline of July 3 for the government and opposition to begin dialogue or see the army impose its plan.
Morsi's office has said he will stick to his own political reconciliation plan.
Egyptian opposition groups have chosen former UN nuclear agency chief Muhammad ElBaradei to represent them in any negotiations.
Opponents of Morsi are massed in Tahrir Square after a deadline they set for him to step down expired earlier on July 2.
Supporters of Morsi are massed in the Nasr City area of Cairo.
A top Muslim Brotherhood leader, Mohamed al-Beltagui, has called supporters to be ready for "martyrdom" to prevent a coup.
At least four ministers who are not Muslim Brotherhood members have tendered their resignations since demonstrations against his administration brought millions of Egyptians into the streets on June 30.
U.S. President Barack Obama called Morsi to express his concerns over the crisis.
The White House said on July 2 that Obama asked Morsi "to take steps to show that he is responsive" to the concerns of his political opponents.
U.S. State Department spokeswoman Jen Psaki told reporters that Washington is not taking sides in the crisis.
"We are on neither side. We are on the side of the Egyptian people," she said. "We have been in touch with all sides, with the opposition, with the government, with the military, and we will continue to be. But to alleviate any concerns or assumptions, we have not taken sides, we are not on any side."
She said Kerry had called Egyptian Foreign Minister Mohamed Kamel Amr to tell him "it is important to listen to the Egyptian people."
The call was made amid reports that Egypt's foreign minister also had resigned.
With reporting by AlJazeera.com, BBC, CNN, and Reuters