Jeanine Áñez, an opposition senator, has declared herself the interim president of Bolivia after the dramatic resignation of Evo Morales.
Ms Áñez said that according to the country's constitution she was the next in line to the presidency.
"Before the definitive absence of the president and vice president... as the president of the Chamber of Senators, I immediately assume the presidency as foreseen in the constitutional order," Ms Áñez said to applause from cheering opposition legislators.
The country's constitutional court has approved her installation as the interim Head of State.
Members of Parliament who were elected on the former president's party did not attend the session calling it a coup by an opposition senator.
Morales is currently in Mexico where he sought asylum after saying that his life was in imminent danger.
On Twitter, the former president reacted calling Áñez's installation as president as the "sneakiest, most nefarious coup in history".
The results of the election that gave Evo Morales victory were questioned by the Organisation of American States after an audit found that there were issues.
Gen Williams Kaliman, Bolivian army chief, had urged Mr Morales to tender his resignation for the sake of peace in the country.
He resigned on Sunday, citing the need to prevent more bloodshed.