Tunisia's Moncef Marzouki faces Sidi Bouzid protest
Protesters have thrown tomatoes and stones at Tunisia's President Moncef Marzouki in Sidi Bouzid, where the Arab Spring started exactly two years ago.
Mr Marzouki was swiftly evacuated by security officers, disrupting his rally to mark the anniversary.
Vendor Mohamed Bouazizi set himself alight in Sidi Bouzid, starting the uprising that ousted the former regime.
The new government has faced a series of protests recently, as people accuse it of failing to improve their lives.
Protesters invaded the square where Mr Marzouki had addressed a crowd of about 5,000 people, AFP news agency reports.
They threw tomatoes and stones, forcing security officers to evacuate him and parliamentary Speaker Mustapha Ben Jaafar.
The protesters shouted "the people want the fall of the government" - one of the rallying cries of the revolution that overthrew long-serving ruler Zine al-Abidine Ben Ali in January 2011.
The unrest then spread to Egypt, Libya and other countries in the Arab world.
In his speech, Mr Marzouki promised economic progress within six months to the residents of Sidi Bouzid, a poor town in central west Tunisia, AFP reports.