Manuel Merino, the little-known head of Peru’s Congress, was sworn in as the country’s new president Tuesday.
About half of the 130 members of Congress are facing criminal investigations on matters including graft and homicide.
Protesters clashed with riot police in central Lima and other cities on Tuesday, carrying flags and signs saying: “Merino isn’t my president.”
Peru Congress ousted the President Martín Vizcarra on Monday in an impeachment vote over corruption allegations, prompting immediate tensions in the Andean nation.
President Martin Vizcarra over allegations he handed out government contracts in return for bribes.
Mr Vizcarra said he would accept the vote, not take any legal action, and leave the presidential palace.
Today I am leaving the presidential palace. Today I am going home,” Vizcarra said during a speech late on Monday, surrounded by his cabinet in the courtyard of the presidential residence in downtown Lima.
Manuel Merino, the speaker of Congress, is expected to assume the presidency until July 2021 – when Mr Vizcarra’s term was due to end.
It is the second attempt over the last two months to oust the president.
Mr Vizcarra, 57, has previously denied allegations that he accepted bribes worth 2.3m soles ($640,000; £487,000) when he was governor of the southern Moquegua region.