Tunisian police fired at an angry crowd of 1,000, killing two people and injuring 17 others.

The official Tunisian news agency said the crowd had attacked the police station after the police chief "abused" a woman. A local journalist said he slapped her during a demonstration, triggering the violence.

The journalist said two other people died on the way to hospital, but that information could not be officially confirmed.

Regional prefect Mohamed Najib Tlijali, calling for calm on a local radio station, said that the police chief had been taken to hospital and was under arrest.

The clash in the north-western town of Kef appeared to be among the most serious since the North African country began a process of moving out of a 23-year-long dictatorship with the flight into exile of President Zine El Abidine Ben Ali on January 14 following a month of demonstrations.

A statement by the Interior Ministry, which is in charge of police, said around 1,000 people threw stones and firebombs at the police station in a surge of anger after the "abuse" by the police chief. The crowd burned two cars, one a police vehicle, the ministry said.

Police fired tear gas, then fired into the air in a vain effort to disperse the crowd, then began firing on demonstrators, the ministry said. It said investigators had been sent to Kef.

Tunisia remains tense since demonstrations pushed Ben Ali into exile in Saudi Arabia. Police in particular were long distrusted by the population because they carried out the repressive policies of his regime.

The demonstrations that set of Tunisia's "people's revolution" began in the nation's heartland when an unemployed man in the central western town of Sidi Bouzid set himself on fire on December 17 after police confiscated his fruit and vegetable stall because he had no legal authorisation to sell.

A woman police officer reportedly slapped the man, in a major affront to his dignity.

The Tunisian uprising has since spread to Egypt where tens of thousands have demonstrated for nearly two weeks calling for the removal of President Hosni Mubarak.