The confrontation began when officials ordered the demolition of houses built on publicly-owned land [Reuters]

Police in Algeria''s capital have used teargas to disperse a crowd of young men who threw stones and petrol bombs to try to stop bulldozers demolishing dozens of illegally built homes.

Wednesday''s riot was unusually violent and took place at a time when Algerian authorities are wary of any sign of contagion from the unrest elsewhere in the Arab world.

A police spokesman said 50 officers were injured in the clashes. Reporters on the spot said the demonstrators replied with iron bars and stones.

The newspaper El Watan said at least five vehicles had been set on fire, including a police truck attacked by young people.

The confrontation, in the Oued Koriche suburb of Algiers, began when local officials ordered the demolition of more than 30 houses built on publicly-owned land without a permit.

Police in protective gear formed a shield around bulldozers which moved in to demolish the houses, but they came under attack from about 100 young men.

After a few hours all the illegal buildings were knocked down and the confrontation ended.

The shortage of housing is a major problem in Algeria, especially in the capital where the buildings are packed tightly together on hills sloping down to the Mediterranean Sea and where there is fierce competition for living space.

Since the start of this year there have been daily rallies after bloody protests against the cost of living claimed five lives and left 800 injured, involving all social classes.

The authorities subsequently announced a series of measures to meet the demands, including more housing.