Bolivia's opposition leader declared herself the country's interim president on Tuesday.
Senator Jeanine Áñez was sworn into the post as the South American country scrambles to restore order after weeks of protests.
Former president Evo Morales resigned after the military asked him to step down. He has said he was forced out in a coup d'état.
Morales has since arrived in Mexico where he was granted political asylum.
Protests broke out in Bolivia after a disputed October 20 election in which Morales, who had been in power for almost 14 years, was reelected.
The Organisation of American States (OAS) said it found "clear manipulations" of the voting system calling into question Morales' slim victory over centrist rival Carlos Mesa.
Áñez said she would "return democracy to the country".
"I will work in this short time because Bolivians deserve to live in freedom, they deserve to live in democracy. Never again will the vote be robbed," the senator said.