Anti-government demonstrators take part in a protest against President Dilma Rousseff's appointment of former President Luiz Inacio Lula da Silva as her chief of staff, in front of the Brazilian national congress in Brasilia, Brazil, March 17, 2016. [Photo/Agencies]

Deliberations could drag on for months. But hotly contested seats on the committee, amid vocal calls from some opposition lawmakers for Rousseff to resign, were spread among all parties in the lower house of Congress.

"The panel includes moderates, allies and opponents of the government," said Leonardo Picciani, leader in the lower house of the centrist PMDB party, Rousseff's main governing partner.

Rousseff and Lula have both denied any wrongdoing.

Brazil's benchmark stock index rallied 6.6 percent, the biggest daily jump in seven years, and the Brazilian real firmed 2.3 percent as the political crisis increased bets that Rousseff's ouster could bring a more market-friendly administration to power.