Jamaat-e-Islami assistant secretary general Abdul Kader Mollah was sentenced to life by a special tribunal here yesterday, sparking riots in different parts of the country.
Five of the six charges against Mollah were proved during the trial.
Authorities called out paramilitary troops to guard the capital Dhaka as political violence between the police and Jamaat-e-Islami activists overnight claimed four lives in the port city of Chittagong.
The Jamaat-e-Islami called a nationwide shutdown for the second consecutive day to halt trials of their several top leaders in two special courts for the 1971 war crimes.
Police fired rubber bullets and tear gas canisters at the outskirts of Dhaka and southwestern Khulna, while protesters exploded home-made bombs in the country's north, but there were no reports of injuries.
Meanwhile, thousands of youngsters thronged a major square here demanding tougher punishment for Mollah, prompting a government decision to appeal against the verdict.
"We have decided to file the appeal in the Appellate Division (of the Supreme Court)...We will file it as soon as possible," attorney general Mahbubey Alam told a news agency.
He said the prosecution would challenge the acquittal of Mollah in one of the six charges in which the International Crimes Tribunal found him "not guilty".
The youngsters, mostly university students, and internet bloggers, angered by the "lenient verdict", converged at the Shahbagh Square at the heart of the city yesterday afternoon and grew in numbers gradually, staging a candle-light vigil throughout the night.
These protesters stayed back at the square defying the Jamaat-e-Islami bandh. PTI
Leading 1971 Liberation War veterans, politicians and cultural activists joined them as they made their makeshift stage symbolically hanging the effigies of major 1971 war crimes suspects.
"I may be a minister or anything else...Being a freedom fighter I don't accept the verdict (against Mollah)", Information Minister Hassanul Haque Inu, said, expressing his solidarity with the protesters at the square.
Several other senior leaders of ruling Awami League and its allies, including ministers, joined the protesters while organisers said their sit-in vigil would continue with more students joining the protest demanding a harsher sentence.
But Jamaat-e-Islami said the war crimes charges against Mollah and eight other senior party leaders including its incumbent chief Matiur Rahman Nizami are bogus and part of a wider political vendetta.
The party enforced a nationwide strike and threatened to call indefinite protests if the trials were not halted.
A series of protests last week by Jamaat-e-Islami activists had left at least nine people dead.
Officials said Border Guard Bangladesh (BGB) were deployed to help police maintain public order in the capital city.
The tension has erupted as war crimes trials in the two special tribunals were believed to have reached their fag end.
A fugitive cleric was handed down the capital punishment in the maiden verdict of one of the tribunals after his trial in absentia last month.
While two of the 10 high profile war crime accused belonged to Bangladesh Nationalist Party (BNP), the main opposition party, the others were Jamaat-e-Islami leaders.
The Jamaat-e-Islami was opposed to Bangladesh's 1971 independence from Pakistan while the party sided with Pakistani troops during the Liberation War when officially three million people were killed.
The tribunals were formed by Hasina's government in 2010.
Dhaka: Clashes between Jamaat-e-Islami activists and the police continued unabated on Wednesday, as violence in Bangladesh claimed four lives after a top leader of the fundamentalist party was given a life term for "crimes against humanity" during the 1971 Liberation war.
First Published: Wednesday, February 06, 2013, 20:52