Nik Abdul Aziz Nik Mat, a revered Islamic spiritual leader who helped bolster unity in Malaysia's opposition bloc and a key advocate of Islamic law, has died at age 84.

His family and his party say Nik Aziz, who was battling prostate cancer, died late Thursday at his home in northeastern Kelantan state.

Nik Aziz, the spiritual leader of the Pan-Malaysian Islamic Party, helped keep his party in an opposition alliance amid calls from conservative members to leave the bloc.

His death is the second big blow to the opposition this week, with alliance leader Anwar Ibrahim jailed for five years Tuesday for sodomy. Analysts say the incidents increase the risk of a split-up in the three-party alliance, which has been beset for months by infighting and growing ideological differences.