CAIRO (AP) -- A young leader of Egypt's anti-government protesters, newly released from detention, joined a massive crowd in Cairo's Tahrir Square for the first time Tuesday and was greeted with cheers, whistling and thunderous applause when he declared: "We will not abandon our demand and that is the departure of the regime."

Many in the crowd said they were inspired by Wael Ghonim, the 30-year-old Google Inc. marketing manager who was a key organizer of the online campaign that sparked the first protest on Jan. 25 to demand the ouster of President Hosni Mubarak. Straight from his release from 12 days of detention, Ghonim gave an emotionally charged television interview Monday night where he sobbed over those who have been killed in two weeks of clashes.

He arrived in the square when it was packed shoulder-to-shoulder, a crowd comparable in size to the biggest demonstration so far that drew a quarter-million people. He spoke softly and briefly to the huge crowd from a stage and began by offering his condolences to the families of those killed.

"I'm not a hero but those who were martyred are the heroes," he said, breaking into a chant of "Mubarak leave, leave." When he finished, the crowd erupted in cheering, whistling and deafening applause.

Ghonim has emerged as a rallying point for protesters, who reject a group of traditional Egyptian opposition groups that have met with the government amid the most sweeping concessions the regime has made in its three decades in power.

Protesters have lacked a clear, representative voice and many worry the traditional parties are trying to hijack the uprising, which began when activists used the Internet to mobilize protester. The mostly youthful protesters are insisting that no concessions will do unless Mubarak steps down.

In his first television interview Monday night, Ghonim dubbed the protests "the revolution of the youth of the Internet" and proclaimed defiantly: "We are not traitors."

About 130,000 people have joined a Facebook group nominating Ghonim as the spokesman of their uprising. The page is called "I delegate Wael Ghonim to speak in the name of Egypt's revolutionaries."

Tuesday's huge turnout in Tahrir gave a resounding answer to the question of whether the protesters still have momentum even though two weeks of steadfast pressure have not achieved their goal of ousting Mubarak.

"The (Wael) interview showed a face of the truth which the state media tried to cover up for so long," said retired Army General Essam Salem. "Many people are coming because they saw the truth."

Fifi Shawqi, a 33-year-old upper-class housewife who came with her three daughters and her sister to the Tahrir protest for the first time, said Ghonim inspired her.

"I saw Wael yesterday (in the interview) and I cried. I felt like he is my son and all the youth here are my sons," she said. "I think Wael brought many, many more."

Others in the crowd said they too were joining for the first time.

"I know many people who came here for the first time after they were impressed by Wael and the pictures of the martyrs," said Iman Ibrahim, a 40-year-old, upper-class housewife.

Even government employees joined the crowed, including about 5,000 university professors and teachers who failed in an earlier attempt to march on the Interior Ministry, where they were blocked by security.

There were demonstrations calling for the president's ouster around the country as well with 18,000 people cramming into the main square of Egypt's second largest city in Alexandria.

Some 3,000 service workers for the Suez Canal also demonstrated in Suez city, while 8,000 people chanted anti Mubarak slogans in the southern city of Assuit.

Meanwhile, Mubarak's regime offered more concessions to the protesters in hopes of appeasing them while keeping as firm a grip on power as it possibly can.

Vice President Omar Suleiman, who is managing the crisis, offered to set up committees to propose long-sought constitutional amendments and monitor the implementation of all proposed reforms. The amendments will include presidential term limits and relaxing eligibility rules for who can run. The two committees will start working immediately, he said.

"The president has expressed his welcome for this national dialogue, emphasizing that it puts our feet on the right path out of this ongoing crisis," he said. He also stressed the need for a "clear roadmap with a specific timetable that will take Egypt to the root of an orderly and peaceful transfer of power with respect for the constitutional legitimacy."

Mubarak has refused the protesters' central demand that he step down, insisting on serving out his term until elections in September.

The Obama administration is not calling for Mubarak's immediate departure, saying a precipitous exit could set back the country's democratic transition. Under Egypt's constitution, Mubarak's resignation would trigger an election in 60 days. U.S. officials said that is not enough time to prepare.

Mubarak also ordered a probe into last week's clashes between the protesters and government supporters as well as mass detentions of human rights activists and journalists. The committee will refer its findings to the attorney-general, Suleiman said.

He also promised there would be no reprisals.

"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 committee considering constitutional and legislative changes will be led by the head of Egypt's highest appellate court and composed of six senior judges and four constitutional experts, according to a statement issued later by the official news agency MENA. It will make its recommendations to Suleiman by the end of this month.

The latest government announcement came two days after Suleiman met for the first time with representatives of opposition groups, including the outlawed Muslim Brotherhood - the country's largest and best organized opposition group - to debate a way out of the ongoing political crisis.

The fundamentalist Islamic group issued a statement earlier Tuesday calling the reforms proposed so far as "partial" and insisting that Mubarak must go to ease what it called the anger felt by Egyptians who face widespread poverty and government repression.

The Brotherhood also accused pro-Mubarak thugs of detaining protesters, including Brotherhood supporters, and handing them over to the army's military police who torture them.

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

The president tried to project business-as-usual Tuesday, receiving the foreign minister of the United Arab Emirates, Sheikh Abdullah Bin Zayed Al Nahyan.

The protests also appear to have emboldened Egyptians elsewhere to seek to settle long-running local disputes.

More than 70 people were wounded Monday night when hundreds of angry residents tried to storm the main police station in the town of Khargah in southern Egypt to demand the ouster of a top police officer who has long had a reputation for heavy-handedness. Police opened fire on the protesters. A security official, speaking on condition of anonymity because he wasn't authorized to release the information, said 13 suffered from gunshot wounds and the rest from tear gas.