A tribunal in Bangladesh has sentenced Islamist leader Delwar Hossain Sayeedi to death for crimes committed during the country's 1971 war of independence.
The Jamaat-e-Islami chief was found guilty of charges including murder, torture and rape. He is the most senior figure convicted so far.
The verdict was cheered by his opponents but set off protests in which at least 30 people were killed.
Critics said the charges were politically motivated.
Lawyers for Sayeedi say they plan to appeal in the Supreme Court.
The Jamaat-e-Islami party rejects the tribunal and staged a strike on Thursday in protest. After the verdict was announced it called a further two-day stoppage for Sunday and Monday.
Thousands of police have been deployed in Dhaka to maintain security.
As well as the 30 killed, at least 300 people were injured in clashes between police and Jamaat supporters across the country, police told the Reuters news agency.
Jamaat was opposed to Bangladeshi independence but denies any role in war crimes committed by pro-Pakistan militias.
Official estimates say more than three million people were killed in the war.
Security was tight around the capital, Dhaka, as the judgement was being read out. On hearing the verdict, protesters gathered at a busy intersection in the city erupted into cheers.
"We've been waiting for this day for the last four decades," one man told local television, the Agence France-Presse news agency reports.
Thousands had staged a protest in the capital on Wednesday, demanding the death sentence be handed down to him.
Recent weeks have seen a series of angry demonstrations demanding the execution of Jamaat leaders being tried by the tribunal. But there have also been protests against the court.
The verdict is the third issued by the controversial tribunal, which is trying a total of nine Jamaat leaders and two members of the Bangladesh Nationalist Party.
Sayeedi was accused of working with the al-Badr group during the independence struggle and carrying out numerous atrocities, including forcibly converting Hindus to Islam.
His critics say that during the war he formed a small group to loot and seize the property of Bengali Hindus and those who supported independence.
The tribunal found Sayeedi guilty of eight out of the 20 charges levelled against him. These were murder, torture, rape and forcibly converting Hindus to Islam.
State prosecutor Syed Haider Ali described the verdict as a "victory for the people", AFP reports. But in court Mr Sayeedi protested, blaming the judgement on the influence of bloggers and pro-government forces.
Earlier this month another Jamaat leader, Abdul Kader Mullah, was sentenced to life for crimes against humanity. Huge crowds have been demanding he be executed.
In January, former party leader Abul Kalam Azad was found guilty in absentia of eight charges of crimes against humanity and sentenced to death.
In the wake of the public outcry calling for the execution of Abdul Kader Mullah, Bangladesh's parliament earlier this month amended a law which will allow the state to appeal against his life sentence.
The special court was set up in 2010 by the current Bangladeshi government to deal with those accused of collaborating with Pakistani forces who attempted to stop East Pakistan (as Bangladesh was then) from becoming an independent country.
But human rights groups have said the tribunal falls short of international standards. Jamaat and the BNP accuse the current government of pursuing a political vendetta.