Brazil's Supreme Court upheld on Thursday the voting order fixed by the lower house of Congress for Sunday's impeachment vote, a setback for President Dilma Rousseff, who is struggling to muster votes to block an opposition bid to remove her from office.

A majority of the justices rejected an injunction sought by the Communist Party of Brazil, a Rousseff coalition ally, to overturn the voting order decided by Speaker Eduardo Cunha, which favors impeachment by having states where anti-Rousseff sentiment predominates vote first. The court must still rule on a request by Rousseff's government to suspend Sunday's vote.