The students had planned to meet at Algiers' central post office, which is a landmark in the capital, and march on government buildings about two kilometres away, but police also turned out in their hundreds.

Demonstrations are currently banned in the north African country, but youths have turned out several times in recent months to confront police equipped with riot shields, helmets, bullet-proof vests and batons.

The students tried several times to break through the police barrier and police began to use their batons, while their opponents threw projectiles made of glass.

Police tried to frighten the students away by rattling their batons against their riot shields, so that the youths were forced to fall back.

At one point, thick black smoke poured out of the top floor of a school next to the University of Algiers, leading to the evacuation of pupils and the arrival of the fire brigade. Pupils told AFP the whole floor had been burnt.

The students then briefly sat down on the ground outside the university entrance before making an attempt to march in the opposite direction, but once again they ran into hundreds of police.

An hour and a half later, several hundred were still milling around with banners reading "For a university open to the world," "Down with the repression of students," and "Down with this regime."

The security forces clearly had the upper hand.

Algeria has been largely unaffected by the popular uprisings that have already toppled the leaderships of Tunisia and Egypt.

However, students wanting political reforms and improved study and living conditions have already demonstrated several times in Algiers and forcefully been halted, with injuries sustained.