Dhaka, Jul 1 (IANS): Bangladesh on Wednesday marked four years of a terror attack at an upscale cafe in Dhaka which claimed the lives of 20 civilians, mostly foreigners, and two policemen.

The attack at the Holey Artisan cafe on this day in 2016 was claimed by the Islamic State (IS) terror group, although the government has held the local militant group Jamaatul Mujahideen Bangladesh (JMB) responsible for it, Efe news reported.

Police later determined that 21 people were involved, 13 of whom were killed during the attack and in subsequent operations.

Canadian-Bangladeshi Tamim Chaudhry, who died in a subsequent police operation, was considered the mastermind.

Of the remaining eight, a Dhaka court in November 2019 acquitted one and sentenced the other seven to death.

Now four years later, Bangladeshi authorities claim to have "successfully" wiped out any extremist threat since the infamous attack on Holey Artisan.

"We strictly controlled the militancy. The few small groups left we are identifying and arresting them," Home Minister Asaduzzaman Khan told Efe news.

"The militancy could not raise its head in our country because the people of our country do not shelter them... We have the example of the mother of a militant handing him to us. This is why we were successful," he added.

The security forces "are working tirelessly to prevent any untoward incident", police headquarters spokesman Sohel Rana told Efe.

Independent analysts, however, have warned against complacency despite significant advances in the fight against terrorism.

"It looks like there is a dramatic decrease in homegrown terrorist attacks in Bangladesh as the government has taken multiple pre-emptive measures to thwart any terrorism-related threats," said Mubashar Hasan, an expert on political Islam at the University of Oslo.

But even if the threat level is low, the concern still exists, according to Shahab Enam Khan, professor of international relations at Jahangirnagar University, near Dhaka.

"There is no threat at the surface level because the standard operating procedure of extremists has changed. One of the major issues is now online radicalization. This is an indirect tension," he told Efe.

Rapid Action Battalion (RAB), or the country's elite police force, acknowledged the threat of online radicalization and insisted that they have been working to mitigate it.