Legal groups have called on Philippine legislators to defend their exclusive constitutional power to prosecute and try impeachable officials, which they say was usurped by Supreme Court justices who ousted their chief justice in an unprecedented ruling last week.

Leaders of legal and human rights groups staged a protest Tuesday in front of the heavily guarded Supreme Court in Manila, carrying a streamer that read, "We dissent, resist authoritarianism, oppose attacks on judicial independence."

Supreme Court justices voted 8-6 Friday to grant a petition by the government's solicitor-general to remove Maria Lourdes Sereno from the 15-member tribunal for allegedly failing to file statements of assets and liabilities as required by law. Sereno denies the allegation and refused to participate in the vote, which her lawyers say she plans to appeal.