Bangladesh authorities on Saturday hanged a top Islamist leader for overseeing a massacre during the nation's 1971 independence war against Pakistan, with hundreds of people in the capital Dhaka celebrating the death of a "war butcher".

Security was tightened outside the jail and across the country as specially trained convicts took Mohammad Kamaruzzaman to a makeshift gallows and hanged him using a rope, in line with Bangladeshi jail procedure.

"Mohammad Kamaruzzaman has been executed at 10:30 pm Bangladesh time (1630 GMT)," Law and Justice Minister Anisul Huq told AFP.

The Islamist was declared dead by a magistrate and a government doctor.

Kamaruzzaman, the third most senior figure in the Jamaat-e-Islami party, was convicted of abduction, torture and mass murder as one of the leaders of a pro-Pakistan militia that killed thousands of people.

The Jamaat party condemned "the government's pre-planned murder of writer, journalist and Islamic scholar" Kamaruzzaman and called a nationwide strike for Monday in protest at the hanging.

Hundreds of people burst into cheers and made victory signs as news of the execution was announced in central Dhaka, where they gathered to celebrate the death of a man they called a "war butcher".

Bangladesh went ahead with the execution despite last-minute pleas by the United Nations, the European Union and human rights organisations to halt the hanging. The UN said the trial did not meet "fair international" standards.

Just hours before the execution, Kamaruzzaman's family visited him at the prison.

"We found him in good health and not worried about his fate at all," his eldest son Hasan Iqbal told AFP after seeing his father.

"In his last comments, he regretted he did not see the victory of Islamic movement in Bangladesh. But he was confident it would be victorious here one day," he said.

Kamaruzzaman, 62, became the second Islamist to be hanged for atrocities during the 1971 war. Abdul Quader Molla, Jamaat's fourth-highest ranked leader, was hanged in December 2013.

Hundreds of Jamaat activists were killed in 2013 when the party held a series of nationwide protests to halt the war crimes trials of its leaders, and tens of thousands were arrested.


Tight security


Police said security was tightened outside the capital's main jail and across the country ahead of the hanging.

An ambulance carrying Kamaruzzaman's body left the jail for his home village in northern Bangladesh more than an hour after the execution, jailor Farman Ali told reporters, adding that the vehicle was escorted by a convoy of elite security officers.

The family had dug a grave at his village in northern Sherpur district where he would be buried on Sunday, Kamaruzzaman's son said.

The country's Supreme Court cleared the last hurdle for Kamaruzzaman's execution on Monday after rejecting his final appeal against the original death sentence handed down by a controversial war crimes court in May 2013.

He was given several days to seek clemency from the country's President Abdul Hamid to avoid death. But his son said his father did not seek any mercy.

"My father said only Allah can give or take life, not a president," he said.


'Village of Widows'


Prosecutors said Kamaruzzaman presided over the massacre of at least 120 unarmed farmers who were lined up and gunned down in the northern village of Sohagpur during the war.

The remote hamlet has since become known as the "Village of Widows".

Kamaruzzaman's defence lawyers argued that he was too young to lead any militia during the war, let alone carry out mass murder. He was 19 years old when Bangladesh's independence war broke out.

The 1971 conflict, one of the bloodiest in world history, led to the creation of an independent Bangladesh from what was then East Pakistan.

Three women who lost their husbands testified against Kamaruzzama in one of the most emotive of all the war crimes trials.

"All 32 widows who are still alive are happy the notorious killer has been hanged. Finally we got justice," said Mohammad Jalal Uddin, a Sohagpur farmer who lost seven members of his extended family in the killing.

Analysts said the execution could deepen the country's political crisis after the main opposition leader, Khaleda Zia, launched nationwide protests in January to try to topple Prime Minister Sheikh Hasina's secular government.

Jamaat, the nation's largest Islamist party, is an ally of Zia's Bangladesh Nationalist Party (BNP).

At least five other Jamaat leaders, including the party's head Motiur Rahman Nizami, have been sentenced to death and their appeals are being heard in the Supreme Court.

Since the start of the year Jamaat's members have been accused of being behind a number of deadly firebomb attacks, including on buses. The violence in the past three months has left at least 120 people dead.

Jamaat and the BNP have said the war crimes trials are mainly aimed at silencing Hasina's opponents rather than delivering justice.

Hasina's government says the trials -- which lack any international oversight -- are needed to heal the wounds of the conflict.