Bangladesh's Supreme Court has upheld a death sentence against a top Islamist political leader for crimes committed during the country's 1971 war of independence from Pakistan.

Motiur Rahman Nizami - leader of the country's biggest Islamist party, Jamaat-e-Islami - was convicted by a special war crimes tribunal last year of a raft of offences that included genocide, murder, torture and rape.

Four opposition politicians, including three leaders of Jamaat-e-Islami, have been convicted by the tribunal and executed since late 2013.

Nizami has been in jail since 2010 when he was charged with war crimes by the tribunal set up by Prime Minister Sheikh Hasina that year. Bangladeshi authorities say about three million people were killed and more than 200,000 women raped during the liberation war.

Islamists have denounced the tribunal as part of a politically motivated campaign aimed at weakening the leadership of Jamaat-e-Islami, a key ally of the country's main opposition party.

Jamaat has called for a nationwide strike on Thursday in protest.

Nizami is accused of setting up the Al-Badr militia, a paramilitary unit accused of collaborating with the Pakistani army in large-scale killings and targeting Bangladesh's Hindu minority and intelligentsia.

A panel of senior Supreme Court judges rejected his appeal, removing the last legal barrier to his execution by hanging unless he is granted a presidential pardon, which analysts see as unlikely.

Rising violence

Attorney General Mahbubey Alam expressed satisfaction with the verdict. Defence lawyers said that they did not get justice.

Khandaker Mahbub Hossain, Nizami's lawyer, said the tribunal targeted the wrong men.

"The entire world knows what the Pakistan army did during the liberation war in 1971. They committed the offence of murder, offence of arson, offence of rape, and mass killing. They are let off," he said.

While Jamaat-e-Islami strongly opposed the independence of Bangladesh and the break-up of Pakistan, it denies any participation in war crimes during the 1971 conflict. 

The executions since 2013 have come amid a rise in violence in Muslim-majority Bangladesh, with armed groups claiming the murder of two foreigners and four secular writers and a publisher last year.

The government has blamed the increase in violence on Jamaat-e-Islami but the party denies any link.

Source: Al Jazeera and agencies