DHAKA (REUTERS) - A Bangladesh war crimes tribunal convicted and sentenced a top Islamist party leader to life imprisonment on Monday, as violence broke out across the country between police and his supporters.

Ghulam Azam, 91, the former head of Jamaat-e-Islami party, was found guilty on charges of planning, conspiracy, incitement and complicity to commit genocide and crimes against humanity during a 1971 war for independence from Pakistan, lawyers and tribunal officials said.

It was the tribunal's fifth conviction since January.