Portuguese Prime Minister Antonio Costa announced his resignation after he was embroiled in a corruption investigation into the awarding of energy-related contracts.

 Portuguese media reported that investigators had searched several ministries as well as Mr. Costa’s offices.

 Public prosecutors said they had indicted Infrastructure Minister Joao Galamba and issued an arrest warrant for Costa’s chief of staff.

 The investigation covers alleged misuse of funds, active and passive corruption by political figures, and influence peddling,” according to a statement from public prosecutors.