Algerian police are struggling to contain more than a thousand protesters thronging the streets of the capital denouncing cartoons of the Prophet Muhammad published by French satirical weekly Charlie Hebdo.

Chanting "I am not Charlie, I am Muhammad," protesters left their mosques after Friday prayers and gathered in downtown Algiers' May 1 square where they were met by hundreds of riot police.

Demonstrations in the capital are forbidden, but only a few people have been arrested so far and police appear content to keep the protesters contained.

The weekly's new issue has a drawing of Muhammad as an act of defiance in the wake of last week's attack at the paper's office that killed 12 people.

Many Muslims view the caricatures of Muhammad as a profound insult to Islam.