Algerians are casting their votes in presidential elections that are likely to lead to Abdelaziz Bouteflika's fourth mandate, despite wide expections of a low turnout amid calls for a boycott with the opposition warning of rigged results. Bouteflika, 77, who is seeking to extend his 15-year rule despite chronic health problems, is the firm favourite between six candidates. He has appeared only rarely on television in recent months, looking frail, after suffering a mini-stroke last year which confined him to hospital in France for three months. Al Jazeera's Mohamed Vall reports.