An Islamist extremist accused of being one of the masterminds of last year's deadly siege at a Bangladeshi cafe was shot dead during a pre-dawn raid Friday in Dhaka, police said.

The bodies of Nurul Islam Marzan and another suspected extremist were found after officers raided a property in the capital's Rayer Bazar neighbourhood, a spokesman for the Dhaka Metropolitan Police told AFP.

"​Marzan and his associate Saddam died in an encounter with police,"​ Inspector General of Police A.K.M Shahidul Haque said.

"He (Marzan) was the operational commander of July cafe attack. He was one of the masterminds of it."

Additional deputy commissioner Yusuf Ali told AFP police had found the body of a "suspected extremist" alongside Marzan, who was aged around 30.

He was "one of the masterminds" of the siege at the upmarket Holey Artisan Bakery on July 1 last year in which 18 foreign hostages were shot or hacked to death, Ali added.

The country's security forces launched a deadly crackdown against Islamist extremists following the cafe siege, which badly undermined Bangladesh's reputation as a relatively moderate Muslim nation.

Since the cafe attack, security forces have shot around 50 Islamist extremists including most of the alleged kingpins of JMB.

The Islamic State (IS) organisation claimed responsibility for the cafe attack, posting images of the carnage as it happened and photos of the gunmen who had posed with the IS's black flag.

Mohibul Islam Khan, the deputy chief of Dhaka police's counter terrorism and transnational crime unit, said Marzan was an Arabic student at Chittagong University before he dropped out and joined an offshoot of Jamayetul Mujahideen Bangladesh (JMB), a homegrown extremist group which has been blamed for the cafe attack.

"Along with Tamim (Ahmed Chowdhury), Marzan planned the Gulshan attack," he said, referring to the Canadian citizen of Bangladesh descent who police described as the main mastermind of the attack.

Chowdhury was killed in another raid outside the capital in August last year.     

Police intelligence had found that Marzan organised the cafe siege and was its operational commander, said Khan. 

Bangladesh is reeling from a wave of attacks on foreigners, rights activists and members of religious minorities.

While many of those attacks have been claimed by IS or Al Qaeda, Prime Minister Sheikh Hasina's secular government has blamed local militants, denying that international jihadists have gained a foothold in Bangladesh.

Critics say Hasina's administration is in denial about the nature of the threat posed by Islamist extremists and accuse her of trying to exploit the attacks to demonise her domestic opponents.

Last September US Secretary of State John Kerry said during a visit to Dhaka that there was evidence to link the extremists behind the recent spate of deadly attacks in Bangladesh to IS.

Source: AFP