CAIRO - Protesters thronged Cairo's Tahrir Square on Tuesday in one of Egypt's largest anti-government demonstrations to date as their movement was energized by a television interview given by a Google executive who for two weeks had been detained by Egyptian security officials.

Wael Ghonim, 30, has emerged as a rallying point for the protesters, particularly for those who reject the talks now underway between President Hosni Mubarak and some opposition groups. In an emotional interview on Monday, hours after his release, Ghonim described his detention and spoke of the promise of the protest movement and his hopes for the nation.

"I am not a hero," he said. "The real heroes are the ones on the ground, those I can't name."

Appearing briefly in Tahrir Square on Tuesday, he said, "We will not abandon our demand, and that is the departure of the regime."

Ghonim, a key organizer of an Internet campaign that led to the street protests beginning Jan. 25, was the star attraction at the rally. He spoke from a stage set up in the center of the square that has now become a tent city of protesters.

With no indication that Mubarak plans to leave before his presidential term ends in September, Egypt's would-be revolutionaries sought to break a stalemate with the government in their bid to topple the autocratic former air force commander who has held power for nearly 30 years.

Hundreds of thousands gathered in what witnesses estimated was the largest crowd in the downtown Tahrir Square since protests began two weeks ago. It was a sign that the anti-government movement was by no means fizzling.

Inside the square, photos of people killed in the demonstrations were displayed. A memorial of "martyrs' clothes" was set up at one entrance to the square. Rocks spelled out the words in English, "GO TO HELL MUBARAK."

Even as banks and restaurants reopened and many Egyptians returned to work, traffic around the square was gridlocked, with tens of thousands of protesters pouring in through army checkpoints. The demonstrators were heeding a call for a general strike, part of a bid to retake momentum in what has shaped up as a test of wills with Mubarak's strongman government.

At stake is Egypt's political future.

Mubarak's new vice president, Omar Suleiman announced the creation of two committees to oversee constitutional changes and other reforms, though he offered no details of who would be tapped to serve on the committees or how much authority they would have.

Suleiman also pledged that the government would not seek retribution against protesters.