But protesters in the streets rejected the new concessions and vowed to keep up their campaign until the 82-year-old president steps down. Many are convinced that the regime wants wear down their movement and enact only superficial democratic reforms that will leave its deeply entrenched monopoly on power in place.

Tens of thousands thronged Cairo’s central Tahrir Square in a 12th day of protests, waving flags and chanting, "He will go! He will go!"

Mubarak, who has ruled Egypt with an authoritarian hand for nearly 30 years, insists he must stay in office until his term ends in the autumn with a September presidential election. The military figures he has installed to lead the government — Vice President Omar Suleiman and Prime Minister Ahmed Shafiq — have offered in the meantime to hold negotiations with the protesters and the entire opposition over democratic reforms to ensure a fair vote.

A day after President Barack Obama pushed Mubarak to leave quickly, the administration changed tone Saturday with a strong endorsement of Suleiman’s plans.

"It’s important to support the transition process announced by the Egyptian government actually headed by now-Vice President Omar Suleiman," Secretary of State Hillary Rodham Clinton said at an international security conference in Munich, Germany. She warned that without orderly change, extremists could derail the process.

A U.S. envoy who met Mubarak earlier this week, former ambassador Frank Wisner, said it is "crucial" that Mubarak remain in place for the time being to ensure reforms go through. He pointed out that under the constitution, a Mubarak resignation would require new elections in two months, meaning they would take place under the current rules that all but guarantee a ruling party victory.

His comment was an abrupt flip in message, a day after Obama called on Mubarak to "make the right decision." The State Department later said Wisner was speaking as a private citizen since the mission to Egypt he was sent on by Obama had ended.

But the protesters have little trust that Suleiman and the regime will on their own bring democracy without the pressure of the mass demonstrations on the street. They want the concrete victory of Mubarak’s removal — though some appear willing to settle for his sidelining as a figurehead holding only his title — with a broadbased transitional government to work out a new constitution.

"What happened so far does not qualify as reform," said Amr Hamzawy, a member of the Committee of Wise Men, a self-appointed group of prominent figures from Egypt’s elite that is unconnected to the protesters but has met with Suleiman to explore solutions to the crisis. "There seems to be a deliberate attempt by the regime to distract the proponents of change and allow the demands to disintegrate in the hope of (regime) survival."

That could mean the crisis could move into a test of sheer endurance, as protesters try to keep drumming out tens of thousands into Tahrir day after day.

The government and military have promised not to try to clear protesters from the square, and soldiers guarding the square continued to let people enter to join the growing rally.

But there were signs of army impatience Saturday. At one point, army tanks tried to try to clear a main boulevard by bulldozing away burned out vehicles that protesters used in barricades during fighting this week with pro-regime attackers. The move prompted heated arguments with protesters who demanded the husks remain in place in case they are attacked again. The troops relented only after protesters sat on the ground in front of the tanks.

There were also reports for the first time of attempts by troops to prevent those entering from bringing food for protesters. "They want to suffocate the people in Tahrir and this is the most obvious attack on them without actually attacking," said Mohammed Radwan after soldiers tried to confiscate some of the bread, cheese and lunchmeat he was bringing in.

The resignation of the leadership of the ruling National Democratic Party appeared to be a new step by Suleiman to convince protesters that he was sincere about reform — or at least convince the broader public so support for the movement fades.

The six-member party Steering Committee that stepped down included some of the country’s most powerful political figures — and the most unpopular among many Egyptians. Among them was the party secretary-general, Safwat el-Sharif, and the president’s son Gamal Mubarak.

Gamal has long been seen as his father’s intended heir as president, a prospect that raised outrage among many Egyptians. The turmoil has crushed those ambitions, however, with Suleiman promising in the past week that Gamal will not run for president in September. Some, though far from all, of the wealthy businessman-politicians that surrounded Gamal and were also deeply unpopular, have also been removed from key posts.

Many in Tahrir dismissed the resignations with scorn. The move will only "reinforce their (protesters’) resolve and increase their confidence because it shows that they are winning, and the regime is retreating inch by inch," said Wael Khalil, a 45-year-old activist among the protesters.

But authorities were projecting an air of confidence they can ride out the unprecedented wave of protests, which have posed the most dramatic challenge to their hold in nearly three decades of Mubarak’s rule.

State TV announced that banks and courts, closed for most of the turmoil, will reopen Sunday, the start of Egypt’s work week, a move to depict that some normalcy was returning to a capital of 18 million that has been paralyzed for nearly two weeks by the crisis.

Shafiq, speaking to journalists on state TV, depicted the protest movement as weakening. He noted that a re-invigorated protest — estimated at around 100,000 people — had failed to force Mubarak out on Friday as organizers had hoped. "All this leads to stability," he said.

He suggested protesters and other opposition forces would eventually enter negotiations with Suleiman over constitutional change. "The level of aspirations is going down day by day," he said.

So far, however, only a couple of official opposition political parties have agreed to talks. The official parties, which operate with regime consent, are not involved in the negotiations, have little popular base and are viewed with contempt by many protesters.

The protest organizers themselves are a mix of small movements who managed to draw broadbased support among a public disenchanted with Mubarak’s rule. The majority are young secular leftists and liberals, who launched the wave of protests though an Internet campaign, but the fundamentalist Muslim Brotherhood also has built a prominent role.

They want a deeper change than Suleiman has offered so far, though the vice president says he is willing to talk about all amendments. They seek a lifting of emergency laws that give the security forces near unlimited powers, an end to restrictions on the forming of political parties, guarantees of independent supervision of elections and the annulling of rules on who can run for the presidency that all but rule out any credible challenge of a ruling party candidate.

The current rules are key to the regime’s lock on power, backed by rampant rigging of elections, by security services widely accused of corruption and a casual use of torture and by party control of the powerful state media.

Most of all, the protesters want Mubarak out, and they insist the talks Suleiman seeks can’t happen until then.

Some protest organizers held their first meetings with Shafiq late Friday, underlining that they met him only to discuss how to arrange Mubarak’s departure. One proposal being floated would have Mubarak deputize Suleiman with his powers while keeping just his title for the time being.

But "the problem is in the president … He is not getting it that he has become a burden on everybody," said Abdel-Rahman Youssef, one of the activists who attended the meeting.

In Tahrir, Elwan Abdul Rahman, a 26-year-old who came from southern Egypt on Friday to join protesters, dismissed the prime minister’s depiction of a fading protest movement.

"He’s laughing at the world, he’s laughing at all of us," he said, pointing at the crowds and saying, "Do you think they’re gonna go away tomorrow?" he said. "People are here with their blood and their soul."

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AP correspondents Hamza Hendawi, Hadeel al-Shalchi and Paul Schemm contributed to this report.