Algerian police have marched to the president's headquarters in an unusual protest movement prompted by violence against security forces.

The unrest in southern Algeria and protests in the capital come amid concerns that President Abdelaziz Bouteflika is too ill to rule Africa's largest country, an ally in U.S. efforts against terrorism. Bouteflika has been largely absent from the public eye since his re-election in April.

A few hundred police officers protested in the capital Wednesday, a day after a similar march Tuesday.

The protesters are showing support for colleagues in the riot-torn southern oasis city Ghardaia, according to local media. About a dozen people have been killed and many shops burned in the riots, as Berber and Arab communities compete for scarce jobs and housing there.