At the same time, the State Department rejected claims that revelations of rampant corruption in leaked U.S. diplomatic documents had sparked the uprising.
The department also issued a travel warning to U.S. citizens, suggesting they forgo travel to the country and consider leaving if already there, and authorized the departure of nonessential U.S. Embassy personnel and of all family members of U.S. staff at government expense.
In a phone call to Tunisian Foreign Minister Kamal Merjan, Clinton offered U.S. support for Tunisia as it transitions from the autocratic rule of ex-President Zine El Abidine Ben Ali. Clinton called for the government to address the underlying causes of the popular discontent that fueled the uprising, such as unemployment and poverty.
"She urged that the government work to re-establish order in the country in a responsible manner as quickly as possible," the State Department said in a statement released as looting and violence continued to rock Tunisia in the aftermath of Ben Ali's ouster on Friday. "She also underscored the importance of addressing popular concerns about the lack of civil liberties and economic opportunities, and the need to move forward with credible democratic elections."
Clinton said she was encouraged by remarks by Prime Minister Mohammed Ghannouchi and interim President Fouad Mebazaa "indicating a willingness to work with Tunisians across the political spectrum and within civil society to build a truly representative government."
A day before Ben Ali fled the country, Clinton delivered a stark warning to Arab leaders that they must open economic and political space to the Mideast's exploding youth population if they wanted to blunt extremism and prevent unrest and rebellion. In a speech in the Qatari capital of Doha on Thursday, Clinton said the foundations of development and progress in the Middle East were "sinking into the sand" and would continue to do so unless reforms were enacted.
Meanwhile Sunday, State Department spokesman P.J. Crowley rejected suggestions that blunt assessments of Ben Ali and his family, their lavish lifestyles and graft contained in cables released by the WikiLeaks website had contributed to discontent over high unemployment and poor economy.
Crowley said in a Tweet that Tunisians were well aware of the situation long before WikiLeaks published the cables and that Tunisians alone were responsible for the uprising.
Many commentators have suggested that the cables contributed to the discontent. Some have said the developments constitute the first "WikiLeaks revolution," something that Crowley dismissed.
"Tunisia is not a Wiki revolution," he said. "The Tunisian people knew about corruption long ago. They alone are the catalysts of this unfolding drama."
The downfall of Ben Ali, who had taken power in a bloodless coup in 1987, delivered a warning to other autocratic leaders in the Arab world.
The improved quality of life for many failed to keep up with the increased limits on civil rights like freedom of expression. The jobless rate is officially 14 percent, but is thought to be far higher among young who make up more than half of its 10 million people.
Tunisians have been living under a government "characterized by corruption, graft, abuse, and repression, and they've been brutalized," Steven Cook of the Council of Foreign Relations told CBS News in an interview Sunday. "They have had no personal political freedom combined with limited economic opportunity."
The self-immolation, and eventual death, of a 26-year-old university graduate selling fruits in central Tunisia last month triggered a series of protests that, relayed by social media like Facebook, spun into general anger against the regime.
Dozens of people have died in a month of clashes between police and protesters angry about the repression and corruption during Ben Ali's rule - unrest that ultimately marked the end of his 23-year regime.
Tunisians are especially overjoyed at the prospect of life without Ben Ali's wife and her family. U.S. diplomatic cables released by WikiLeaks discussed the high levels of nepotism and corruption displayed by her clan.
The cables described the extravagances of Ben Ali and his cronies, particularly those of his wife, Leila Trabelsi, whose family had financial interests from banking to car dealerships. Looters and vandals have hit some of those interests in the days since the president left amid street protests and violence.