The crowd of anti-government protesters gathered in the Egyptian capital's Tahrir Square were energized Tuesday, by the appearance of a newly-freed Google marketing manager turned political activist.

Immediately following his release from 12 days of detention, 30-year-old Wael Ghonim went straight to the central Cairo square where he was greeted by tens of thousands of cheering supporters.

Ghonim, who was one of the key organizers of the online campaign that first drew protesters into the streets of cities across Egypt on Jan. 25, has emerged as a rallying figure for protesters disappointed with the traditional opposition groups that have so far undertaken negotiations with the regime of embattled President Hosni Mubarak.

Addressing the massive, adoring crowd assembled in the square Tuesday, Ghonim implored the gathering not to annoint him their hero.

"I'm not a hero but those who were martyred are the heroes," he said before breaking into a chant of "Mubarak leave, leave."

His appearance came as Egypt's battle of wills stretched into its third week of calls for Mubarak's ouster, and the nearly-30-year president's continued vows to ride out his term.

In his latest attempt to satisfy the demands of his detractors, Mubarak on Tuesday established committees to recommend changes to the country's constitution as well as oversee all his proposed reforms.

Vice President Omar Suleiman made the announcement on state television, promising that both committees will get to work immediately.

Suleiman also said Mubarak has ordered investigations into last week's violent clashes between pro- and anti-government demonstrators as well as mass detentions of human rights activists and journalists. Their findings will be referred to Egypt's attorney general.

"The youth of Egypt deserve national appreciation," Suleiman quoted the president as saying. "They should not be detained, harassed or denied their freedom of expression."

The officially outlawed Muslim Brotherhood -- which nevertheless remains the Egypt's largest and most organized poltical opposition group -- issued a statement Tuesday calling proposed reforms "partial" and accusing pro-Mubarak thugs of rounding up protesters and handing them over to be tortured by army police.

"We call on the military, which we love and respect, to refrain from these malicious acts," the Brotherhood said in its statement.

According to Human Rights Watch clashes have claimed at least 297 lives in the 15 days since protests began. And, a spokesperson for the U.S.-based organization says the toll based on visits to seven hospitals in three cities is likely to rise.

"Actual numbers are probably a bit higher than that because there's a few small hospitals that we have not been able to reach, as well as some other cities where casualties may have occurred," Peter Bouckaert said in an interview with Â鶹´«Ã½ Channel, noting the agency's particular concern with the number of people who have suffered head injuries after being shot with rubber bullets and tear gas cannisters.

But the thousands of protesters camped out in Cairo's Tahrir Square show no signs of uprooting the makeshift village that has taken shape there.

"At the moment, it's a stalemate," CTV's Middle East bureau chief Martin Seemungal said in an interview from Cairo Tuesday.

"If they try to stay or escalate their demonstrations they're going to face an army that has taken a strong stand in trying to contain things," Seemungal said of the resolute crowds who continue to occupy the square in central Cairo.

"They're also going to run into public opinion in wider Egypt and Cairo where a lot of people believe they've got about all they're going to get and they should declare victory now."

But, Seemungal added, protesters are convinced leaving the square before Mubarak steps down would not only mean losing their strongest bargaining chip, but also risking prosecution or persecution by the government.

"Essentially, they do not trust this regime so they're staying in the square," he said.

Even as Mubarak has made a series of concessions in recent days, demonstrators maintain they will not be satisfied until he is out of office.

The 82-year-old president insists he will serve the remainder of his six-year term before planned elections next September.

On Friday, longtime ally U.S. President Barack Obama seemed to welcome Mubarak's quick departure in his suggestion that the Egyptian president should now "do the right thing."

But U.S. State Department spokesperson P.J. Crowley has since made it clear the White House does not believe Mubarak's immediate resignation -- and the election that is legally required to follow 6o days later -- would be prudent.

"A question that that would pose is whether Egypt today is prepared to have a competitive, open election," Crowley told reporters Monday.

"Given the recent past, where, quite honestly, elections were less than free and fair, there's a lot of work that has to be done to get to a point where you can have free and fair elections," he said.

"It is doable within eight months," Crowley added, referring to the vote set for September. "But a lot depends on what happens from this point forward."

For his part, Mubarak went about official state business on Tuesday, meeting with the United Arab Emirates' foreign minister Sheikh Abdullah Bin Zayed Al Nahyan.

With files from The Associated Press and CTV's Martin Seemungal in Cairo