Protesters on Monday hurled rocks at Tunisia's President Moncef Marzouki and parliamentary speaker Mustapha Ben Jaafar in Sidi Bouzid, cradle of the revolution that erupted exactly two years ago.
The incident began after a speech by Marzouki and as Ben Jaafar was about to address the crowd in the poor Tunisian town, where muted celebrations are taking place to mark the anniversary of the uprising.
Tunisia's marginalized interior has witnessed frequent outbreaks of social unrest amid bitter frustration at the revolution's failure to bring material benefits.
The security forces swiftly evacuated the two men to the prefecture, or regional government headquarters, an AFP journalist reported.
The protesters invaded the square where the speeches were taking place, shouting "the people want the fall of the government."
The police held back, after violent clashes in Tunisia in recent few months, often following attempts by the security forces to disperse protesters angry over the government's failure to improve living conditions.
When the president took to the podium on Monday, many in the crowd of around 5,000 started shouting "Get out! Get out!" -- one of the rallying cries of the revolution that toppled the regime of former dictator Zine El Abidine Ben Ali.
Marzouki had promised economic progress within six months, after meeting residents of Sidi Bouzid, who complained about the lack of infrastructure.
Poverty and unemployment were key factors behind the mass protests that erupted after a 27-year-old street vendor set himself on fire outside the governor's office on Dec. 17, 2010, to protest against police harassment.
Ongoing insecurity and the crisis in Europe have hampered Tunisia's economic recovery, after last year's recession, and unemployment, pegged at around 18 percent, is especially high among young Tunisians, fuelling their anger and frustration.
Last month, around 300 people were wounded in five straight days of clashes between police and protesters in the town of Siliana, southwest of Tunis, where a strike swiftly degenerated into violence.