The president of Peru and one of his leading political rivals are due to be questioned by prosecutors investigating payments to politicians by Brazilian construction company Odebrecht.
President Pedro Pablo Kuczynski and former congresswoman Keiko Fujimori have been summoned by anti-corruption prosecutors in separate investigations.
Both were told to appear behind closed doors but Ms Fujimori rebuffed previous summons and may do so again.
The president and Ms Fujimori, leader of the Popular Force party in Congress, have denied wrongdoing.
The questions come shortly after Mr Kuczynski narrowly avoided impeachment over the corruption allegations and then set off protests by pardoning jailed former president Alberto Fujimori.
Many Peruvians believe the pardon was done to secure support from another political party led by Fujimori's son.
The former chief executive of Odebrecht has admitted that company executives paid bribes and campaign contributions to secure public works contracts.
Mr Kuczynski, a 79-year-old former Wall Street banker, was already unpopular when an opposition-led investigative committee revealed documents showing Odebrecht made 782,000 dollars (£581,000) in payments to his private consulting firm more than a decade ago.
The payments were made during years Mr Kuczynski served as a Peruvian government minister.
Ms Fujimori came under scrutiny because of an apparent reference to her when she was a presidential candidate in 2011 found on the phone of the former Odebrecht chief executive, who admitted to Peruvian prosecutors that the company gave money to her.
She denies that her party received any money from the company but has not submitted to questions by prosecutors on three previous occasions.