A Brazilian senator facing charges in an explosive corruption scandal said on Saturday that President Dilma Rousseff "knew everything" about the scheme, deepening the political crisis dividing the Latin American giant.
Senator Delcidio do Amaral, a former Senate leader for the ruling Workers' Party, said in an interview that embattled ex-president Luiz Inacio Lula da Silva masterminded the graft scheme at state oil company Petrobras and that Rousseff used some of the proceeds to fund her presidential campaigns.
"Lula directly negotiated the appointment of Petrobras's directors with the different parties in Congress and knew exactly what the parties did with the directorships, mainly in terms of financing their campaigns," Amaral told weekly magazine Veja.
"Dilma inherited and benefited directly from this system."
An irate Rousseff ordered her government to press criminal charges against Amaral for his "defamatory statements," which she categorically denied.
It is the latest damaging allegation from the senator, who on Tuesday accused Rousseff of trying to buy his silence when he was detained in the Petrobras case.
He made that accusation as part of a plea bargain in return for a lighter sentence -- the kind of deal investigators have used repeatedly to implicate a steadily growing list of rich and powerful figures.
Brazilian politics has been upended by the scandal, after 13 years of dominance by Lula and Rousseff's leftist party.
Investigators accuse Petrobras executives of colluding with contractors to overbill the company by billions of dollars, bribing politicians and parties to keep the system going.
The crisis has triggered angry protests laying bare sharp divisions in Brazil.
Mass rallies for and against the leftist president have rocked the country in recent days, just months before it hosts the Olympics in Rio de Janeiro in August.
Rousseff's enemies are demanding her departure, while her supporters accuse them of attempting a "coup."
Some 270,000 government supporters took to the streets in more than 50 cities Friday, according to police. Organizers put the turnout at 1.2 million.
That was far fewer than the three million that police estimated were at anti-government rallies last Sunday.
In Sao Paulo, about 100 people protesting against the government were gathered Saturday on the major Paulista avenue, brandishing signs reading "Lula the thief" and "Get out Dilma."
"We're going to stay here until she leaves," said one protester, Bruno Balestrero, a 27-year-old actor.
More anti-government protests were expected Sunday.
Rousseff fighting the odds
The latest twist in the Petrobras saga closes out a rough week for Rousseff.
The president is fighting impeachment proceedings, a painful recession and a firestorm over her decision to name Lula as her chief of staff.
A Supreme Court judge blocked the appointment Friday over allegations the president is trying to shield her mentor from arrest in the Petrobras case.
The injunction bars Lula from joining the government until the full Supreme Court rules on the matter.
The court will not convene again until March 30, according to legal news site Jota.
In the interim, the crusading anti-corruption judge heading the Petrobras probe, Sergio Moro, can order Lula's detention -- but only if he can show "evidence to justify it," such as indications that the ex-president would interfere in the investigation, said legal scholar Carlos Goncalves.
Friday also saw the first session of a new congressional committee charged with recommending whether to impeach Rousseff over allegations of manipulating the government's accounts.
The recommendation will go to the full lower house of Congress, where a vote by two-thirds of the 513 lawmakers would trigger an impeachment trial in the Senate.
In that event, Rousseff would be suspended from her duties for up to 180 days. A two-thirds vote in the 81-member chamber would remove her from office.
Rousseff's approval rating is hovering around 10 percent.
A new poll Saturday found that 68 percent of Brazilians would support impeachment, up eight percentage points from a month ago.
"The odds of a government change are definitely increasing," said Joao Augusto de Castro Neves, a senior Latin America analyst at the consultancy Eurasia Group.
Political scientist Wladimir Gramacho said he gave the government a five- to 10-percent chance of escaping the crisis.
"The most likely exit from the crisis is either for the president to resign or for Congress to impeach her," he said.