Brazilian President Dilma Rousseff's grip on power was slipping Wednesday after more allies abandoned her in the fight against an impeachment drive which she has branded a coup.
The 68-year-old leader moved closer to being driven from office in a political and economic crisis rocking Latin America's biggest country less than four months before it hosts the Olympic Games.
With pressure rising after two blocs in Rousseff's ruling coalition announced they would vote to impeach her, she canceled her appearance at a ceremony to light the Olympic flame on Wednesday.
Tuesday's defections swelled the number of lawmakers likely to back a motion against her when the lower house of congress votes Sunday on whether an impeachment trial should be launched.
Polls published in the Brazilian media indicate opposition parties are closing in on securing the 342 votes needed to approve the impeachment motion and send it to the Senate for a further vote.
Leading newspaper O Estado de Sao Paulo on Wednesday calculated on Wednesday that the number of lawmakers who have now decided to support impeachment has risen to 302 -- but dozens have yet to state a position.
Analysts say the desertion on Tuesday of two of Rousseff's key allies, the PP and PRB parties which have 69 lawmakers between them, could prompt a stampede.
"If all the medium-sized parties abandon her, Rousseff will have no way to survive impeachment," said political scientist David Fleischer of Brasilia University.
One of Rousseff's last remaining coalition allies, the PSD party with 36 votes, called a meeting in Brasilia on Wednesday to decide on its position.
Another party, the PR, was scheduled to meet on Thursday. It has 40 seats. Between them, the two parties could swing the vote against Rousseff in the 513-seat Congress.
Rousseff is in the final stretch of a bruising attempt to save her presidency over charges that she illegally manipulated government accounts to mask the effects of recession during her 2014 re-election.
On Tuesday she branded her vice-president Michel Temer a traitor and coup-plotter after an audio recording was leaked in which he was heard practicing the speech he would make if Rousseff is impeached.
"The conspirators' mask has slipped," she said.
"We are living in strange and worrying times -- times of a coup, and of pretending, and betrayal of trust."
Protesters both for and against Rousseff have called for demonstrations this weekend in Brasilia. Security forces have put up fences to protect government buildings from possible disturbances.
Lawmakers who have yet to declare their position were facing fierce lobbying, including from Rousseff's top ally and predecessor as president, Luiz Inacio Lula de Silva.
But he too faces pressure: the courts have suspended his appointment as Rousseff's chief of staff over a corruption case against him.
Brazil's political system has been paralyzed by a huge corruption scandal at state oil company Petrobras. The charges against Lula are linked to that case.
The country has sunk meanwhile into its worst recession in decades.
"Deputies are thinking about their chances of being re-elected" in the next elections, scheduled for 2018, said Fleischer.
Backing Rousseff is highly politically risky since her popularity has plunged so much, he added.
If the lower house votes by two thirds to move forward with the motion, the Senate must then hold a vote on whether to hold an impeachment trial.
"In the Senate it will be even harder to stop impeachment, because the PMDB (Temer's party) is the strongest there," said Michael Freitas Mohallem, a political analyst at the Getulio Vargas Foundation in Rio de Janeiro.
Financial markets have been betting against Rousseff, with stock prices in Brazil rallying as her chances of being impeached have risen.