Burkina Faso's interim parliament has passed a law blocking politicians allied to ousted President Blaise Compaore from running in elections due later this year.
MPs who backed Mr Compaore's unconstitutional bid last year to extend his 27-year rule would be barred from office, the law states.
The vote comes after the arrest this week of several allies of Mr Compaore.
The former president was deposed after violent mass protests in October.
For the latest news, views and analysis see the BBC Africa Live page.
The West African state is currently being led by an interim government, which is hoping to organise presidential and parliamentary elections in October. They will be the first elections since the overthrow of Mr Compaore.
The former ruling party, the Congress for Democracy and Progress (CDP), has opposed the new law.
A spokesman for the party, Boubacar Bouda, told the BBC that it was waiting to see if it was unconstitutional.
Three former ministers are among the eight allies of Mr Compaore whose arrests have been confirmed by the authorities. They include the former ministers of interior, mining and infrastructure - Jerome Bougouma, Salif Kabore and Jean-Bertin Ouedraogo respectively.
The police said on Tuesday that they were investigating the three ministers for "alleged embezzlement".
Meanwhile, unions have called for a general strike over high living costs.