Senegalese police on Sunday cracked down on protests against the postponement of the presidential election, as parliament prepared to debate a bill that would reschedule the vote for August and extend President Macky Sall’s mandate.

Sall announced on Saturday the Feb. 25 vote would be delayed to an unspecified date due to a dispute over the candidate list and alleged corruption within the constitutional body that handled the list. Some opposition and civil society groups have denounced the move as an “institutional coup”.

Lawmakers will on Monday debate a proposal to hold the vote on Aug. 25 and keep Sall in power until his successor is installed, according to the text of the bill seen by Reuters.

African Union Commission Chairperson Moussa Faki Mahamat said in a statement late on Sunday that Senegal should “organize the elections as soon as possible, in transparency, peace and national harmony”.

“It (AU) strongly encourages all political and social forces to resolve any political dispute through civilized consultation, understanding and dialogue..,” the statement added.

Senegal has never delayed a presidential vote and uncertainty about what happens next threatens to fuel further unrest like the deadly protests of recent years that have tarnished its reputation as one of West Africa’s most stable democracies.

In an early sign of pushback, groups of protesters on Sunday blocked traffic at various points along a main thoroughfare in Dakar with makeshift barricades of burning tires.

In one area, around 200 people retreated into side streets after police in riot gear fired tear gas and started detaining protesters.

At least two opposition presidential candidates were swept up in the melee. In an online post, candidate Daouda Ndiaye said he was attacked by police, and the campaign manager of Anta Babacar Ngom told Reuters she had been detained by security forces and was being held into the evening.

Former prime minister Aminata Toure also said she had been detained and taken to a police station in Dakar as soon as she got out of her vehicle.

“President Macky’s exit slip is now marked with the seal of this unprecedented democratic regression,” Toure posted on Saturday in response to the postponement.

The police did not immediately reply to a request for comment. Further protests are planned outside parliament on Monday.

After Sall’s televised announcement, the Economic Community of West African States (ECOWAS) expressed concern about the circumstances that led to the postponement and called for a new election date to be set quickly.

The French foreign ministry on Sunday also urged the authorities “to remove the uncertainty surrounding the electoral timetable, so that the elections can be held as soon as possible and in compliance with the rules of Senegalese democracy”.