Hundreds of Algerians marched on Tuesday against an election called for December, chanting "we will not vote until the regime men are removed".

The planned vote has set up a new phase in the showdown between protesters and the state. Mass protests broke out in February, forcing the veteran president Abdelaziz Bouteflika to stand down in April, and have continued every week since then to demand a more thorough purging of the ruling elite.

During the spring and summer, the government detained a host of senior figures on corruption charges, but it has also started to put more pressure on protesters, arresting opposition leaders and deploying more police at demonstrations.

Powerful army chief Lieutenant General Ahmed Gaed Saleh has for months pushed for an election, saying it is the only way out of the standoff, and on Sunday interim president Abdelkader Ben Salah said it would take place in December.

Since Bouteflika's resignation, fewer people have attended the weekly protests on Tuesday and Fridays, but those still marching have rejected any election for now, saying there could not be a fair vote while the old guard retains power.

Whether Sunday's announcement of a presidential election, and the heavier police presence at demonstrations, will quell the protests or reignite them is likely to become clear during the marches in the coming weeks.

Protesters on Tuesday chanted "We will not stop our protests" and "civilian state, no military state", and demanded the resignation of both Ben Salah and Prime Minister Noureddine Bedoui.

Two former prime ministers, two former intelligence chiefs, eight ministers and several prominent businessmen have been put in custody after being questioned by judges as part of anti-graft investigations.

However, two prominent opposition figures, Karim Tabou and Lakhdar Bouragaa, have also been detained in recent weeks on charges of "contributing to weakening the army's morale".

Samir Belarbi, a well-known activist, was detained on Monday, two lawyers said, though there was no official confirmation from the justice ministry.