Police have arrested 11 people and searched 20 town halls in provinces across Spain in the latest corruption and fraud investigation to rattle the country.

The court headquarters for the northeastern region of Catalonia said the raids Tuesday were part of a parallel probe into the alleged practice by Convergence — one of the region's ruling parties — of charging businesses a commission in exchange for awarding public works projects.

The court said raids were carried out in small towns in Catalonia, the Madrid region and elsewhere.

No details were released on the identity of those detained.

Anger over perceived widespread political corruption was one of the main issues for voters in Spain's recent general election.