Portuguese Prime Minister António Costa says he is resigning after being involved in a widespread corruption probe. Costa said in a nationally televised address that “in these circumstances, obviously, I have presented my resignation to the president of the republic.” Earlier the state prosecutor said police have arrested Costa's chief of staff while raiding several public buildings and other properties as part of a widespread corruption probe. An investigative judge issued arrest warrants for Costa’s chief of staff, the mayor of Sines, and three other people.