Vizcarra, who was vice president in the previous regime, said he would form a completely new cabinet but asked for all lawmakers to help him restore the public's trust in institutions, which had been damaged by the political crisis.

"We have the obligation to respond to the needs, demands and aspirations of all Peruvians, and not get tangled in a bitter struggle that does enormous damage to Peru," said Vizcarra, a former governor of a small mining region, in his inauguration speech to Congress.

He takes office as a scandal involving Brazilian construction conglomerate Odebrecht continues to roil one of Latin America's most stable markets and the world's No. 2 producer of copper.

On the eve of his swearing-in, thousands of protesters marched through downtown Lima to demand early elections, in hopes of purging a political class widely seen as corrupt.

Former President Pedro Pablo Kuczynski, whom Vizcarra replaces, offered to step down this week in the face of near-certain impeachment over his ties to Odebrecht.

He blamed his downfall on the right wing party, Popular Force, that won a majority of congressional seats despite losing the presidency in 2016.

Vizcarra said Peru's justice system must act independently and swiftly to sort the guilty from the innocent, and warned that no branch of government should trample another.

Since serving as the country's ambassador to Canada for the past six months, Vizcarra has largely steered clear of Kuczynski's troubles, which culminated with vote-buying allegations.

Vizcarra, 55, was a civil engineer and governed Moquegua in southern Peru before he teamed up with Kuczynski for the 2016 presidential ticket.

Australian Associated Press