A Bangladesh tribunal sentenced the former chief of the country's biggest Islamic party to spend the rest of his life in prison for crimes against humanity committed during the country's war of independence four decades ago.

Ghulam Azam, 91, was found guilty of torture and the murder of unarmed people during the 1971 struggle, prosecutor Sultan Mahmud said at media briefing. He was charged with collaborating with the Pakistan Army during the conflict when the Jamaat-e-Islami sought to prevent the birth of Bangladesh.

This latest and possibly most explosive sentence from the war crimes panel may reignite clashes between Jamaat supporters and security forces that have followed previous verdicts. Jamaat called a countrywide daylong shutdown to protest the ruling. Street violence erupted in parts of the country on the eve of the judgment, the Daily Star newspaper reported.