At least three close allies of Burkina's Faso's ousted ruler Blaise Compaore have been arrested, their party has said.
The arrests came ahead of a protest by members of the former ruling party against plans to bar Mr Compaore's associates from contesting presidential elections due in October.
Mr Compaore was deposed in a popular uprising in October.
The West African state is currently being led by an interim government.
Mr Compaore's Interior Minister, Jerome Bougouma, is among those arrested, former ruling party member Leonce Kone, told the AFP news agency.
The arrests showed that Burkina Faso's new rulers were "harassing" officials linked to the ousted government, he said.
The authorities have not commented on the arrests.
Supporters of the former ruling party have protested in the capital, Ouagadougou, against a proposed electoral law which will prevent Mr Compaore's allies from running for the presidency.
Mr Compaore is exiled in Ivory Coast. He ruled Burkina Faso for 27 years.