Peru's Congress has sworn in the Vice-President, Martín Vizcarra, to replace the sitting president who resigned amid allegations of corruption this week.
Mr Vizcarra is expected to serve out Pedro Pablo Kuczynski's term, which ends in 2021.
Speaking after the ceremony, he said tackling corruption would be a priority for his government.
But he also urged all sides to put an end to a politics of confrontation and work together to achieve growth.
"This is a new beginning for Peru," he said.
"We need to define clear goals for the country, leaving aside political differences."
Mr Vizcarra, 55, said that in a few days he would appoint a completely new cabinet.
"I propose a social pact to fight corruption and encourage growth, with social integration", he said.
There were calls from the opposition for him to call fresh presidential elections.
His message to Congress, however, was clear - he intends to stay in power until the end of the current term.
For that he will need the support of the opposition, led by politicians loyal to Peru's most divisive figure, former president Alberto Fujimori.
His promise to investigate corruption allegations against his immediate predecessor, Mr Kuczynski, will get the support of Fujimoristas in Congress.
Mr Fujimori's daughter Keiko, who leads the Popular Force party, wished the new president good luck.
"This is a time for all Peruvians to be united," she tweeted.
A former governor of a mining-rich province, Mr Vizcarra is seen as business-friendly but some Peruvians have questioned whether he has the political experience to handle the presidency at a time of crisis.
To add to the pressure on the new president, Peru will be hosting the Summit of the Americas in three weeks' time, which US President Donald Trump has said he will attend.
Peruvian ex-leaders in hot water
- Ollanta Humala, who governed from 2011 to 2016, was ordered in July to spend up to 18 months in jail while while money-laundering charges are prepared against him. He is accused of accepting money from Odebrecht to bankroll his election campaigns, which he denies.
- Alejandro Toledo (governed 2001-2006) is suspected of accepting $20m (£14m) in bribes from Odebrecht, which he has denied. Peru is expected to formally request his extradition from the US, where he is believed to be hiding, in the coming weeks. Peru has offered a reward of $30,000 for any information leading to his capture.
- Alberto Fujimori (in power 1990-2000) was pardoned in December 2017 by President Kuczynski on humanitarian grounds. He had been serving a 25-year-sentence for human rights abuses and corruption during his time in office.
- Francisco Morales Bermúdez (who ruled 1975-1980) was sentenced to life in prison last year over the disappearance of 23 Italian nationals during the 70s and 80s.
Earlier on Friday, Peru's Congress voted overwhelmingly to approve Mr Kuczynski's resignation.
He had tendered his resignation letter on Wednesday, on the eve of a planned impeachment vote against him in Congress.
His position had become untenable after the opposition released secret videos and audios that appeared to implicate him in efforts to buy support from opposition legislators to reject the motion.
Mr Kuczynski, a former Wall Street banker, went on national television on Wednesday to reject the claims.
He said the tapes and audios had been edited to incriminate him.
Mr Kuczynski enjoyed immunity from prosecution as president. But with allegations of corruption against him mounting, he could now face trial.
He was accused of taking bribes from the Brazilian construction company, Odebrecht.