Brazil's President Dilma Rousseff (L) and former president Luiz Inacio Lula da Silva attend the appointment of Lula da Silva as chief of staff, at Planalto palace in Brasilia, Brazil, March 17, 2016. [Photo/Agencies]

Prosecutors accuse Lula of concealing ownership of an oceanfront apartment that was built and furnished by one of the Petrobras contractors in the graft scheme.

The widening bribery scandal has divided Rousseff's fractious coalition and moved the PMDB closer to breaking with her government.

Vice President Michel Temer, leader of the PMDB, did not attend the swearing-in of Lula because Rousseff appointed a lawmaker from his party as civil aviation minister, Temer's aides said. A PMDB convention on Saturday banned its members from taking new posts in her government.

($1 = 3.65 Brazilian reais)