Spain's acting Prime Minister Mariano Rajoy said on Wednesday it would still be impossible to form a government and end a near eight-month political deadlock unless the Socialist party offered him some form of support in a confidence vote.
Rajoy got the green light on Wednesday from his conservative People's Party (PP) to negotiate with centrist rival Ciudadanos and try and secure their support.
But without the Socialists, which have repeatedly said they would veto a PP-led government, he would still be short of a parliamentary majority in a vote to invest him as prime minister.
"Ciudadanos has taken a step forward, the Socialist party has not taken a single one. Without this step, it is not possible for the investiture to go through," Rajoy told a news conference.