Tens of thousands of anti-government demonstrators flooded Cairo's Tahrir Square on Friday in what is being billed as a "Day of Departure," a final attempt to topple the government of President Hosni Mubarak after more than 10 days of violent protests and deadly street battles.

Egyptian Defense Minister Mohamed Hussein Tantawi visited the square and spoke with the largely non-violent protesters, the most prominent government official to do so since the unrest began to demand an end of Mubarak's nearly 30 year rule. 

Soldiers checked IDs to ensure those entering were not police in civilian clothes or ruling party members and performed body searches at the square's entrances, a sign that Egypt's most powerful institution was sanctioning the demonstration -- though Tantawi tried to convince those he spoke to end it.

Protesters labeled the rally the "Day of Departure," a reference to their demand for Mubarak to step down Friday. Some held up signs reading, "Now!" Others chanted "Leave! Leave! Leave!"

Mubarak, who insists he will serve out the remaining seven months of his term, told ABC News he wants to step down, but that doing so would spark chaos. He also vowed not to leave Egypt.

The Obama administration said it was consulting with top Egyptian officials about the possibility of Mubarak immediately resigning, and an interim government forming before free and fair elections this year.

"The president has said that now is the time to begin a peaceful, orderly and meaningful transition, with credible, inclusive negotiations," a White House spokesman, Tommy Vietor, said late Thursday. "We have discussed with the Egyptians a variety of different ways to move that process forward, but all of those decisions must be made by the Egyptian people."

White House and State Department officials would not discuss details of the discussions U.S. officials are having with the Egyptians. Vice President Joe Biden spoke with Egyptian Vice President Omar Suleiman on Thursday, a day after a similar conversation between Suleiman and Secretary of State Hillary Rodham Clinton. Officials said neither Biden nor Clinton made a specific call for Mubarak to resign immediately but pressed for measures that would ease tensions on the streets and set the stage for democratic elections.

U.S. officials said the creation of a military-backed caretaker government was one of several ideas being discussed between the Egyptian regime and the Obama administration. The U.S. officials spoke on condition of anonymity to discuss the continuing sensitive talks. Among the options was a proposal for Mubarak to resign immediately and cede power to a transitional government run by Suleiman, the officials said.