CAIRO, Egypt — Tens of thousands of people, all on their feet, crowded Cairo’s central Tahrir Square on Thursday, expecting an announcement from President Hosni Mubarak that he would resign.

Egyptian state TV reported that Mubarak would speak to the nation from his palace in Cairo on Thursday evening.

The crowd, one of the biggest since the mass protests began more than two weeks ago, chanted, “He’s leaving! He’s leaving!”

The rumors that Mubarak would give a speech and possibly announce his resignation began earlier Thursday afternoon when a senior Egyptian military official said to protesters in local media that, “All your demands will be met today.”

The rumor quickly gained steam around the world as international news organizations picked up on the story. NBC reported that two independent sources had confirmed that Mubarak would step down and that his vice president, Omar Suleiman, would take over. CNN reported that CIA Director Leon Panetta also expected Mubarak to resign Thursday.

U.S. President Barack Obama on Thursday urged Mubarak to immediately begin the process of handing over power, although he stopped short of calling for Mubarak to leave office right now.

"What is absolutely clear is that we are witnessing history unfold," he said in comments ahead of a scheduled speech at Northern Michigan University, adding that this was a "moment of transformation" for Egypt.

In Tahrir Square the excitement was palpable. Few protesters could believe that this grassroots movement might actually succeed in forcing Mubarak, who has held power for three decades, to resign.

Many of the protesters, old and young, were hugging and crying as they waited for Mubarak’s speech, which would be televised on a large white sheet in Tahrir Square.

“I can’t control my emotions tonight, I can’t wait for Mubarak to leave,” said Mohamed Abdel Moez, 44, who sobbed as he videotaped the crowd with his camera phone. “I will be so happy.”

Although many were happy that Mubarak might finally resign, some expressed concern that his vice president, who is also unpopular, would be assuming power and that the parliament would not be disbanded.

“It won’t be good enough for Mubarak to step down,” said Eman Magby, 27. “Parliament has to step down too if I am going to leave this spot.”

The entire crowd repeatedly sang Egypt’s national anthem and waved large Egyptian flags. Several Tunisian flags were also waved. Egypt’s revolution was partly inspired by the uprising in Tunisia that forced out President Zine el-Abidine Ben Ali after more than three decades in power.

A group of about 15 men stood on top of a burned out van that once belonged to the country’s feared security forces in a symbolic scene that demonstrated just how far the protesters had come since the first few days of demonstrations when police violently cracked down on the movement.

Rumors swirled around the square Thursday that a senior military commander might assume power, which was given some credence by reports in local media.

The armed forces supreme council was said to have convened earlier Thursday to begin the orderly transition of power.

Protesters in Tahrir Square Thursday, however, made it clear that nothing short of a Western-style democracy would satisfy them, demanding the departure of the prime minister, the parliament, the president, vice president and refusing any system led by the military.

“We don’t want an army-led regime,” the crowd chanted at one point.

Some, after enduring more than three decades of unflinching rule, couldn’t believe that Mubarak might actually step down.

“I don’t think he will resign. He is too stubborn,” said Yasir, 47, who has been protesting everyday since the demonstrations began on Jan. 25. “He is only concerned with himself.”