Security was tightened in a Bangladesh southern city Sunday ahead of the expected execution of a senior Islamist extremist whose group has been linked to the murder of foreign hostages, police said.

Asadul Islam, a leader of the Jamayetul Mujahideen Bangladesh (JMB) who is also known as Arif, is due to hang in Khulna after the Supreme Court upheld his death sentence in August for blasts that killed two lower court judges in 2005.

Bangladesh has blamed the JMB for the July 1 attack on an upmarket Dhaka restaurant in which 22 people, mostly foreign hostages, were killed.

Security forces have since launched a deadly crackdown against extremists linked to the attack, shooting dead nearly 40 people including its new leader Tamim Chowdhury, a Canadian citizen of Bangladesh descent.

After the attacks, courts have also fast-tracked prosecution of the Islamists. Scores of them were already facing death sentences.

‘The tentative time of his hanging is 10.30 pm (1630 GMT). We've stepped up security all over the city,’ Khulna Police Commissioner Nibhas Chandra Majhi told AFP.

Majihi said hundreds of police and the elite Rapid Action Battalion have been deployed in Khulna, the country's third largest city, to prevent any violence.

In August, just weeks after the cafe attack, Bangladesh's highest court led by the chief justice dismissed Arif's final appeal, clearing the way for his execution.

Arif later refused to seek presidential clemency, paving the way for his hanging later on Sunday, said a prison official of the jail where the Islamist was set to be executed.

Six other top officials of the JMB, including its founding leader Shaikh Abdur Rahman, had already been executed in March 2007 for the same case.

Founded in the late 1990s by Islamists who fought in the Afghan wars along with the Mujahideens and the Taliban, the JMB has sought to impose sharia law in the Muslim majority but secular nation of 160 million people.

On August 17, 2005, the group conducted more than 400 small blasts in 63 of the country's 64 districts. Many of these bombs targeted secular courts.

Hundreds of JMB extremists including Rahman, his deputy Siddiqul Islam alias Bangla Bhai, were later hunted down by security forces in a massive Islamist crackdown.