Spain's acting prime minister Pedro Sanchez said today that he would not accept that far-left Podemos leader Pablo Iglesias be part of his government.
Spain is at a crunch time, with parliament voting next week on whether Sanchez can stay on as prime minister.
Podemos has consulted party members on whether the party should demand that its top officials be in government in order to back Sanchez.
The outcome is expected later today or tomorrow.