Fresh clashes have erupted in Tunisia after police opened fire and killed four people overnight, opposition officials say.
Rioters were hurling stones at government buildings and police were firing tear gas in the capital, Tunis. The trouble came as youths angry about unemployment defied a government curfew aimed at calming more than three weeks of violent protest.
A demonstrator was shot and killed yesterday and an American journalist injured in the riots, a witness said.
The witness, who asked not to be named because of fears for his safety, saw police firing on protesters near the state radio headquarters.
He said the journalist was injured in the leg but police did not appear to be targeting him.
Police were deployed on key thoroughfares in Tunis, which until this week had been spared the violent unrest erupting in provincial towns. Stores around the capital were shuttered.
The interior ministry building and a municipal services building were among targets of protesters' anger.
Tunisia's president later ordered prices on food staples to be slashed and suggested he will not run for re-election.
Zine El Abidine Ben Ali, in a televised speech last night, pledged to end internet censorship and to open up the political playing field.
He said the 75-year age limit on presidential candidates should remain untouched. That would mean Mr Ben Ali, who is 74, would not be able to run in 2014.
He spoke after nearly a month of protests that have left 23 dead according to official figures, dozens more according to opposition figures.
A French and a Swiss citizen were among those killed, the two European governments said.
The Swiss foreign ministry said a woman with dual Swiss- Tunisian citizenship died in northern Tunisia. Swiss radio reported she was killed by a stray bullet while watching a protest a day earlier.
Another victim was a professor of computer science in France, at the University of Technology at Compiegne. Slah Nebti, a Tunisian teacher, said Hatem Bettahar was shot by police in a protest in the central city of Douz. He filmed a video of the shooting's aftermath and posted it to Facebook. It showed Mr Bettahar lying in a pool of blood, and the crowd shouting "God is great!" in Arabic.
Mr Ben Ali has maintained an iron grip on Tunisia since grabbing power 23 years ago.
The image of stability and religious moderation helps draw millions of mostly European visitors a year to the Mediterranean beaches of this small North African nation, making tourism the mainstay of the economy.