Brazilian president Dilma Rousseff's chances of surviving impeachment diminished as three parties abandoned her governing coalition in 24 hours.
The pull-outs came as politicians prepare for a crucial vote on the question expected this weekend.
The departure of the mid-size centrist parties sparked growing despondency among members of Ms Rousseff' left-leaning Workers' Party ahead of the vote expected on Sunday in the Chamber of Deputies.
That vote will decide whether the impeachment process moves ahead based on allegations that Ms Rousseff's administration violated fiscal rules.
The pro-impeachment camp needs two-thirds of the 513 votes in the lower house, or 342 votes, to send the proceedings to the Senate for a possible trial.
According to a tally by the newspaper Folha de S Paulo, 284 members have come out for impeachment, while 114 are opposed and 115 are undecided.
While the outcome is still too close to call, the pull-outs by the majority of the 36 deputies for the Social Democratic Party, the Progressive Party with 47 deputies and the Brazilian Republican Party with 22 made it harder for Ms Rousseff to defeat the vote.
In rare positive news for the government, leaders of the Democratic Labor Party pledged to cast their party's 20 votes against impeachment.
Ms Rousseff has seen her approval ratings tumble amid the worst recession in decades and a spike in both joblessness and inflation.
Meanwhile a sprawling probe of corruption at the state-run energy company Petrobras over the past two years has ensnared dozens of senior politicians across the political spectrum as well as some of Brazil's richest and most powerful business executives.
The president appeared simultaneously defiant and conciliatory on Wednesday, sketching out her plans for "once this page has been turned".
Speaking at an event about the modernisation of Brazil's port infrastructure, she pledged that "starting next week" her administration would reach out to even its enemies in a bid to get the country back on track.
Ms Rousseff and her supporters say the allegations are bogus and insist financial manoeuvres like the ones she made are common practice, used by two previous presidents.
She has repeatedly denounced the proceedings as an attempted coup and a blatant power grab by her enemies.
If the pro-impeachment camp wins Sunday's vote, the proceedings move to the Senate, where a vote would decide whether to begin a trial against Ms Rousseff.
If that happened, she would immediately be suspended from office and vice president Michel Temer would take over.