* Second verdict in trials concerning 1971 independence war
* Police clash with demonstrators in capital, other cities
* Jamaat party denounces tribunal, enforces national strike
A war crimes tribunal sentenced a senior leader of Bangladesh's biggest Islamist party to life in prison on Tuesday, the second verdict in trials that have reopened the wounds of Bangladesh's 1971 independence war and sparked violent unrest.
At least three people were killed in violent protests after Abdul Quader Mollah, 64, was found guilty of charges including murder, rape, torture and arson during Bangladesh's war to break away from Pakistan.
Mollah's Jamaat-e-Islami party called for a national strike that shut shops and businesses to extend into Wednesday, and party activists skirmished with police in the capital, Dhaka, and other towns after the verdict.
In the southeastern city of Chittagong, one person was killed when police opened fire and used truncheons during demonstrations, police and witnesses said. Later on, witnesses said two people had been killed as Jamaat activists fought police.
In the evening, paramilitary forces were deployed at Dhaka's key locations including government buildings, courts and major intersections.
Prime Minister Sheikh Hasina set up the tribunal in 2010 to investigate abuses during the 1971 conflict, in which about 3 million people died and thousands of women were raped.
But critics say she is using it as a political weapon against the two biggest opposition parties, the Bangladesh Nationalist Party (BNP) and Jamaat-e-Islami.
The court delivered its first verdict last month, sentencing a former member of Jamaat-e-Islami and popular Islamic preacher to death.
Hundreds of war veterans had massed outside the court demanding that Mollah should also be sentenced to death, and thousands of people from different professions marched in the capital after the verdict with the same demand.
State prosecutor Mohammad Ali said: "We wanted his death and are surprised by the lesser punishment handed out by the tribunal."
But Jamaat's acting secretary-general, Rafiqul Islam Khan, said the conviction had been was "state-managed".
"The tribunal pronounced the verdict as per the instruction of the government," he said in a statement.
Quader Mollah made a "V" for victory sign as he got into a car after the verdict.
In an indication of the rifts opened up by the court, shops and businesses in the capital and elsewhere were shut as Jamaat-e-Islami enforced a national strike against the verdict and extended it into Wednesday.
The party is demanding that the government dissolve the tribunal and release all of its leaders facing trial, including former and current chiefs and their top lieutenants.
Bangladesh became part of Pakistan at the end of British rule in 1947 but broke away in 1971 after a war between Bangladeshi nationalists, who were backed by India, and Pakistani forces.
Some factions in what was then East Pakistan opposed the break with Pakistan, and numerous abuses were committed during the nine-month war. Jamaat denies accusations that it opposed independence and helped the Pakistani army.
Another 10 people, including two from the BNP, are awaiting trial by the tribunal.
Begum Khaleda Zia, Hasina's arch rival and leader of the BNP, has called the tribunal a "farce".
The ruling Awami party has rejected accusations that the tribunal is biased but it has been criticised by human rights groups for failing to adhere to standards of international law.
Eight people have been killed in recent weeks in violence related to the trials. About 150 people have been injured and a similar number arrested, police have said.