After a mostly peaceful protest on Friday by hundreds of thousands of Algerians the museum of antiquities and a primary sdchool in the capital Algiers were set on fire.
Some of the museum's artifacts were looted - the culture ministry said criminals and not the protesters were to blame.
The protesters want their ailing and absent eighty two year old president to step down.
But Abdelaziz Bouteflika insists he'll stand for a fifth term in power, even though he remains in hospital in Geneva for unspecified medical treatment.
His only concession, that he'll stand down after just a year if he wins the election in April.
On Thursday he issued his first warning to protesters, saying the unrest, now entering its third week, could create chaos in the oil- and natural gas-producing North African country.
Algerians, desperate for jobs and angry at unemployment, corruption and an elderly elite seen as out of touch with the young, have taken to the streets since Feb. 22
The protesters have made every effort to demonstrate peacefully - many of them remember the brutal civil war in the nineties which killed two hundred thousand people.
Some clashes between youths and police broke out on Friday evening and state media said 110 protesters and 112 policemen had been hurt in the unrest.
There were also protests in Paris and other French cities.
President Bouteflika's government is run by members of the National Liberation Front party or FLN. They're dominated by aging veterans of the independence war against France which ended in 1962.
But a few cracks in their hold on power are appearing - there are reports that some of the FLN's lawmakers have resigned.