CAIRO -- Nobel Peace laureate Mohamed ElBaradei, Egypt's top democracy advocate and a key challenger to President Hosni Mubarak, returned to the country Thursday night after declaring he was ready to lead the grass-roots protest movement to a regime change.
Violence escalated outside the capital Cairo. In the flashpoint city of Suez, east of Cairo, rioters -- some wearing surgical masks or scarves over their faces to ward off tear gas -- attacked the main fire station in downtown and looted it before torching it with firebombs.
Firefighters jumped out windows to escape the flames, as heavy black smoke billowed from the burning building. In the northern Sinai area of Sheik Zuweid, several hundred bedouins and police exchanged live gunfire, killing a 17-year-old man.
Social networking sites were abuzz with talk that Friday's rallies could be some of the biggest so far calling for the ouster of Mubarak after 30 years in power. Millions gather at mosques across the city for Friday prayers, providing organizers with a huge number of people already out on the streets to tap into.
By Thursday evening, Facebook, Twitter and Blackberry Messenger services were interrupted, possibly a move by authorities to hamper protesters from organizing.
Egypt's ruling party said it was ready for a dialogue with the public but offered no concessions to address demands for a solution to rampant poverty and political change heard in the country's largest anti-government protests in years. Safwat El-Sherif, the secretary general of the National Democratic Party and a longtime confidant of Mubarak, was dismissive of the protesters at the first news conference by a senior ruling party figure since the protests began.
"We are confident of our ability to listen. The NDP is ready for a dialogue with the public, youth and legal parties," he said. "But democracy has its rules and process. The minority does not force its will on the majority."
The 82-year-old Mubarak has not been seen in public or heard from since the protests began Tuesday with tens of thousands marching in Cairo and a string of other cities.
Mubarak has not said yet whether he will stand for another six-year term as president in elections this year. He has never appointed a deputy and is thought to be grooming his son Gamal to succeed him despite popular opposition. According to leaked U.S. memos, hereditary succession also does not meet with the approval of the powerful military.
Mubarak has seen to it that no viable alternative to him has been allowed to emerge. Constitutional amendments adopted in 2005 by the NDP-dominated parliament has made it virtually impossible for independents like ElBaradei to run for president.
Mubarak's administration suffered another serious blow Thursday when the stock market crashed. The benchmark index fell more than 10 percent by close, its biggest drop in more two years on the back of a 6 percent fall a day earlier.
The protesters have already achieved a major feat by sustaining their demonstrations for three days in the face of a brutal police crackdown. Seven people have been killed, hundreds hurt and nearly 1,000 detained.
The government has banned all gatherings and police have fired rubber bullets, tear gas, and used water cannons to disperse crowds. They have also fired live ammunition in the air at time to warn people and there have been many scenes of riot police in helmets and shields charging crowds and beating people with batons and plainclothes police beating demonstrators with long sticks.
Some of the worst unrest Thursday was in the hot spot of Suez. The protesters also stoned lines of helmeted riot police with shields, who fired back with rubber bullets, water cannons and tear gas. Debris and rocks littered the streets. Demonstrators ran through white clouds of tear gas and kicked the canisters back at police. Some shielded themselves with overturned metal dumpsters and hurled rocks from behind the makeshift barricades. Police said 30 people were injured in the melee.
In the Suez Canal city of Ismailia, east of Cairo, hundreds of protesters clashed with police who used tear gas and batons to disperse them.
Associated Press reporters saw scores of protesters outside the downtown Cairo offices of Egypt's lawyers' union, which has been one of the flashpoints of this week's unrest.
There were two other small, peaceful protests by lawyers in the Mediterranean port city of Alexandria and the Nile Delta town of Toukh, north of Cairo.
ElBaradei, who has emerged as a prime challenger to Mubarak's rule, told reporters at the Vienna airport on his way back to Egypt that he was seeking regime change and ready to lead the opposition.
"The regime has not been listening," ElBaradei said. "If people, in particular young people, if they want me to lead the transition, I will not let them down. My priority right now ... is to see a new regime and to see a new Egypt through peaceful transition."
When ElBaradei touched down in Egypt, he was greeted by a small group of family and friends and reporters.
"It's a critical time in the life of Egypt, and I have to participate with the Egyptian people," he said.
A spokesman for ElBaradei, Abdul-Rahman Samir, said the former head of the U.N. nuclear watchdog was expected to join protests planned for after the Friday prayers.
ElBaradei urged authorities to exercise restraint with protesters expressing their "legitimate need" for an Egypt that is democratic and based on social justice.
ElBaradei returned to Egypt last year after living abroad for decades and has created a wave of support from reformists. But he so far insisted he would not run in this year's presidential election unless restrictions on who is eligible to contest the vote are lifted and far reaching political reforms are introduced.
His support base is primarily made up of youths and he is seen as untainted by corruption. But his detractors say he may be lacking a thorough understanding of life here because of the decades he has lived abroad, first as an Egyptian diplomat and later with the United Nations.
In another boost to the protest movement, the country's largest opposition group -- the outlawed Muslim Brotherhood -- also threw its support behind the demonstrations. If the group's backers join the protests on Friday, it could swell the numbers on the streets significantly. But the group has stopped short of an outright call for its backers to turn out.
The Muslim Brotherhood called on its website for protests to remain peaceful. It also called for new parliamentary elections under judicial supervision, the introduction of far-reaching reforms and the lifting of emergency laws in force since 1981.
The Brotherhood made a surprisingly strong showing in parliamentary elections in 2005, when it won 20 percent of seats and served as the main opposition bloc in the legislature. In the latest parliament elections held in November, the Brotherhood failed to win even a single seat. It decried widespread fraud by the ruling party and boycotted the runoffs.
The vote gave the ruling party all but a small fraction of the chamber's 518 seats, an outcome that analysts say chipped away further at the regime's legitimacy and likely contributed to the discontent being vented on the streets this week.
"The movement of the Egyptian people that began January 25 and has been peaceful, mature and civilized must continue against corruption, oppression and injustice until its legitimate demands for reform are met," said the statement.
"We are not pushing this movement, but we are moving with it. We don't wish to lead it but we want to be part of it," said Mohammed Mursi, a senior Brotherhood leader.
The stock market crash, which brought year-to-date losses to almost 21 percent, hit at the core of some of the regime's main accomplishments. The president has built his legacy continuing and expanding the open market policies launched by his predecessor, Anwar Sadat, in the 1970s.
While Egyptian officials have boasted about healthy economic growth figures, critics have argued that ambitious economic reforms have done little more than make the rich even richer while poverty, unemployment and prices rise unabated.