An Algerian military court has detained a prominent left-wing politician as it investigates an alleged plot against the country's leadership.

A statement from the Workers Party says its general secretary Louisa Hanoune was ordered held in custody Thursday at the military court in Blida.

The statement says Hanoune is being questioned as a witness in an investigation into the former president's brother Said Bouteflika and two former intelligence bosses. Several tycoons have also been targeted in a corruption crackdown.

The outspoken Hanoune has been a fixture on Algeria's political scene since 1991, and her detention shocked many. The party called it "counter to the Algerian people and their revolutionary mobilization."

A peaceful uprising helped push longtime leader Abdelaziz Bouteflika from power last month, but new protests are planned Friday.