Updated

The Obama administration on Wednesday sharply warned Bahrain against violent crackdowns on anti-government demonstrators as unrest worsened around the Middle East.

The warning came as U.S. Secretary of State Hillary Rodham Clinton urged Egyptians to hold true to the ideals of their revolution while she toured Cairo's Tahrir Square, the symbolic heart of the peaceful uprising that toppled Egypt's longtime autocratic leader last month.

Carrying a message similar to that which she delivered in Egypt earlier in the day, Clinton arrived late Wednesday in Tunisia, where protesters demanding democratic freedoms inspired reformers around the Arab world. They succeeded in ousting their authoritarian ruler in January.

Clinton was to hold meetings with Tunisia's transitional leaders on Thursday, encourage civic leaders to press ahead with calls for change and pledge U.S. support for greater political, economic and social openness.

Clinton's democracy cheerleading tour to Egypt and Tunisia came as the situation in Bahrain deteriorated with soldiers and riot police expelling hundreds of protesters from a square in Bahrain's capital, using tear gas and armored vehicles. At least five people were killed Wednesday as clashes flared across the kingdom, according to witnesses and officials.

Bahrain, a strategic ally of the United States because it hosts the Navy's 5th Fleet, has sought and received hundreds of reinforcements for its security forces from neighbors like Saudi Arabia, raising fears of an escalation in violence and descent into the near civil war that is embroiling Libya. Forces loyal to Libyan leader Moammar Gadhafi have pressed ahead with assaults on opposition-held towns.

In Washington, President Barack Obama called both King Hamad bin Isa Al Khalifa of Bahrain and King Abdullah of Saudi Arabia to express deep concern over the violence in Bahrain. He "stressed the need for maximum restraint," White House spokesman Jay Carney told reporters. Obama "also stressed the importance of a political process as the only way to peacefully address the legitimate grievances of Bahrainis and to lead to a Bahrain that is stable, just, more unified and responsive to its people."

Clinton called the situation "alarming" and said Bahrain and neighbors were on "the wrong track" by trying to quell unrest with troops instead of reform. Bahrain's majority Shia population has been chafing for years under the absolute rule of a Sunni monarchy and, emboldened by revolts in Tunisia and Egypt, has begun to more forcefully call for changes.

"We have deplored the use of force," Clinton told reporters in Cairo before flying to Tunis. "We have said not only to the Bahrainis but to our Gulf partners that we do not think security is the answer to what is going on."

In Egypt, Clinton heaped praise on the anti-government demonstrators whose peaceful protests in the central Tahrir Square ousted President Hosni Mubarak on Feb. 11. And she said she hoped people everywhere would look back on the revolt and regard it as "one of the most important historic turning points" in the Middle East.

"The pyramids are magnificent but nowhere near as magnificent as what you have already done," she told American and local Egyptian employees at the U.S. Embassy. She called on them to help protect the achievement so that "no one is permitted to hijack this revolution, no one is permitted to turn the clock back on this revolution, no one is permitted to claim it for only one group of Egyptians and exclude other Egyptians."

"That will be the challenge," she said. "And we will help in any way possible."

Clinton's visits to Egypt and Tunisia are aimed at encouraging the Egyptian and Tunisian people and their transitional leaders to hold true to the ideals of democratic reforms that propelled their revolutions. In a speech she delivered on Jan. 13 in Doha, Qatar, Clinton warned Arab governments that they risked "sinking into the sand" if they did not meet the needs of their people. A day later, Tunisian President Zine El Abidine Ben Ali fled his country amid mass protests demanding his ouster.

Clinton told Egyptians that thanks to them, their country is now rising and is expected to say the same in Tunisia, where she will hold a town hall meeting with civic leaders and rights activists. Her trips underscore U.S. concern that gains made since Mubarak's and Ben Ali's departures may be lost to impatience or to the rise of an extremist or authoritarian new leadership.

In Egypt, civic groups have raised fears that the timing of a weekend referendum on constitutional amendments and June parliamentary elections followed by a presidential vote are too rushed to permit a true representative democracy to emerge. Some believe the timing won't give secular opposition groups enough time to organize into credible political parties.

The most organized opposition movement in the county is the Muslim Brotherhood, an Islamist party long banned by Mubarak. The brotherhood took a low-key role in the initial protests against Mubarak but is now seen as moving to take advantage of the space opened by the protesters in Tahrir Square.

Surrounded by a heavy contingent of U.S. and Egyptian security guards, Clinton took an unscheduled 15-minute stroll through the square, smiling, waving and shaking hands with bystanders who thronged her. Many thanked her for visiting the heart of the anti-government demonstrations while others fought for a glimpse or a photo of the secretary of state, the highest level U.S. official to visit Egypt since Mubarak stepped down on Feb. 11.

"It's just a great reminder of the power of the human spirit and universal desire for freedom and human rights and democracy," Clinton told reporters as she navigated the square. "It's just thrilling to see where this happened."

Without mentioning any political parties, Clinton said the revolution must remain inclusive and urged Egyptians to build on the euphoria Tahrir Square spawned by embracing universal values. She gave that message to interim Prime Minister Essam Sharaf and the chief of Egypt's powerful Armed Forces Supreme Council, Field Marshal Hussein Tantawi.

On Tuesday, Clinton unveiled details of an economic support package aimed at helping to create badly needed jobs, mainly for Egypt's exploding youth population, and spur foreign investment. In addition to an already announced $150 million being redirected to the transition and the financial sector, the aid will include tens of billions of dollars in credits and private-sector loans as well as the expansion of Egyptian facilities eligible to send duty-free exports to the United States.

Clinton also addressed the ongoing violence in Libya, saying support was growing in the international community for tougher action against Gadhafi's regime. The turning point was the Arab League's expression of support over the weekend for a no-fly zone over the country.

"That was an extraordinary statement," Clinton said, noting that Arab nations were asking the U.N. Security Council to take action against one of their own. "There is intense negotiation occurring in New York over the terms of a resolution that would include a range of actions that the international community could take."