TEHRAN,Young Journalists Club (YJC) - Vizcarra, who had been serving as both vice president and his country's ambassador to Canada, took the oath of office and donned the red-and-white presidential sash before the Peruvian Congress.
The ceremony came shortly after lawmakers voted to accept Kuczynski's resignation, rather than push ahead with impeaching him over corruption allegations.
"We will stand firm in the fight against corruption. Transparency will be a pillar of our administration," said Vizcarra, a former cabinet minister known for his meticulous management and unflashy style.
"Better times will come," he told his fellow Peruvians in his first address as president.
Just a day before, the engineer and technocrat was far removed from the political hornet's nest that brought down Kuczynski, leading a relatively placid diplomat's life in Ottawa.
He flew home Thursday night, on his 55th birthday, and now takes over the remainder of Kuczynski's term, until 2021 -- though early elections are still possible.
Kuczynski, 79, had a short tenure as president: the former Wall Street banker was elected by a razor-thin margin in June 2016, and took office the following month.
But he lacked a majority in Congress, and was almost immediately embroiled in a messy conflict with the main opposition party, Popular Force, led by Keiko Fujimori, the daughter of disgraced ex-president Alberto Fujimori.
When reports emerged linking Kuczynski to Brazil's scandal-plagued construction giant Odebrecht -- accused of paying massive bribes to politicians around Latin America for juicy public works contracts -- Popular Force mounted a relentless push to remove him from office.
Odebrecht revealed in December that it had paid nearly $5 million to consulting companies linked to Kuczynski when he was finance minister.
The former president survived a first impeachment vote that month. Three days later, he granted a pardon on medical grounds to former president Fujimori, who had been in jail for corruption and human rights violations.
That sparked speculation of a back-room deal with an opposition faction led by Keiko Fujimori's brother and rival Kenji.
When video tapes emerged of Kenji -- who has now split from his sister's party -- apparently offering bribes to a fellow lawmaker to vote against the December impeachment, the political damage to Kuczynski proved to be too much.
Facing a new impeachment vote, he announced his resignation Wednesday, proclaiming his innocence but saying it was best for the country if he quit.
Source: AFP