The Durga Puja celebrations have concluded in Bangladesh even as another Hindu devotee was found dead on Saturday amidst days of communal unrest and violence unleashed by unidentified Muslim miscreants who vandalised temples over alleged blasphemy, leading to the deployment of paramilitary forces in more than half of administrative districts.

Authorities overnight imposed a nationwide security vigil while officials said that initial investigations have thrown up crucial evidence against the perpetrators of violence against the minority Hindu community's Durga Puja.

The paramilitary Border Guard Bangladesh (BGB) has expanded the vigil from 22 to 34 out of 64 administrative districts.

The elite anti-crime Rapid Action Battalion (RAB) said it expects to arrest some of the key perpetrators of the sporadic violence which took place in the past three days.

Voicing optimism over the investigation, Home Minister Asaduzzaman Khan Kamal told reporters that "we expect developments of the investigations in the next one or two days".

The police, meanwhile, said that they have recovered the body of a Hindu devotee from a pond near a temple in southeastern Begumganj sub-district of Noakhali.

According to a Hindu community leader, the deceased was a victim of bigot attacks on devotees on Friday.

Four people were killed and scores of others injured during clashes between Muslim bigots and the police at Hajiganj sub-district in central Chandpur on Wednesday and Thursday, prompting the government to call out paramilitary forces to maintain law and order across the country.

With the latest killing, the death toll during the Durga Puja celebrations across the country has reached five.

On Thursday, Prime Minister Sheikh Hasina promised to bring to justice the culprits behind the violence, saying anyone involved in the attacks on Hindu temples and Durga Puja venues in Comilla will not be spared.

"The incidents in Comilla are being thoroughly investigated. Nobody will be spared. It doesn't matter which religion they belong to. They will be hunted down and punished," she said while exchanging greetings with the Hindu community members during an event at Dhakeshwari National Temple in Dhaka on the occasion of Durga Puja.

The violence had erupted after an alleged blasphemy incident at a Durga Puja pavilion in Cumilla, bordering Chandpur and about 100 kms from Dhaka, after which a probe was launched.

Sporadic clashes continued on Friday between police and bigots while extreme right-wing Islamic Shashontantra Andolon on Saturday took out a big procession in downtown Dhaka's Purana Paltan area protesting what they called as "demeaning of the "Holy Quran".

The armed police equipped with water cannons and other riot gear kept a sharp vigil from a close proximity.

The Durga Puja celebrations, considered to be the biggest festival of the minority Hindu community in Bangladesh, concluded without the traditional Bijoya Dashami procession.

Due to the COVID-19 situation, the procession was not carried out this year.

Besides, the idols were immersed on Friday at around 4PM instead of 12 PM out of respect for the Jumma prayers of the majority Muslim community, the Dhaka Tribune newspaper reported.

As sporadic attacks and vandalism reported on Friday as well, authorities issued prohibitory orders in the Noakhali district, banning public gatherings in Chaumuhani municipality from dawn to dusk on Saturday, it said.

The mob attacked, vandalised and looted Hindu households, businesses, and several temples in Chaumuhani during their march, the report said quoting the police.

The government and law enforcement agencies described the incidents as planned with the aim of destabilising the country.

In Sylhet, locals and the police on Friday foiled attempted vandalism at two pavilions in the city's Hawlader Para area. The attackers hurled bricks at the pavilions as well as adjacent houses, the report said.

More than 150 people, brandishing sharp-edged weapons, took out a march and tried to attack the Kalibari pavilion. However, as the devotees protested, the mob marched towards the Hawladar Para area and broke the gate of another pavilion, the report said.

According to the police, Facebook and YouTube were largely used to instigate communal tensions while reports said that the Bangladesh Telecommunication Regulatory Commission (BTRC) identified more than a hundred identities which were used to spread instigative comments.

Mobile phone operators said that under the BTRC directives, they stopped the 3G and 4G internet connectivity for 12 hours on Friday which the authorities said were done due to "unavoidable reasons".

"The violence appeared to be part of a plot against interfaith harmony and the perpetrators were involved in identical incidents in the past as well," said Colonel KM Azad of RAB that draws men from the Army and other armed forces including the police.

"We are preparing to take stringent legal actions and arrest some of them very soon," he said.

This year, the Durga Puja began on October 11.

Hindu devotees paid tribute to Goddess Durga for four days and immersed the idols in rivers on the fifth and final day on Friday.

This year, Durga Puja was celebrated at 32,118 puja pavilions across the country, including 238 in the capital Dhaka, the report said.