DHAKA: Dhaka police on Saturday arrested eight people, including a prominent leader of the opposition BNP, in connection with Friday's arson attack on a train in the heart of Dhaka that left at least four people dead, ahead of elections in Bangladesh boycotted by the opposition.

Four carriages of the Benapole Express that runs from Benapole, bordering West Bengal, were set on fire at around 9 pm on Friday at the Gopibagh area, less than two km from its destination of the capital's Kamalapur Railway Station.

The eight persons arrested include Dhaka south city unit BNP joint convener Nabi Ullah Nabi and five activists of Jubo Dal, which is the main opposition Bangladesh Nationalist Party's youth wing.

"Nabi Ullah Nabi and Jubo Dal activist Mansur Alam were among the planners and financers of the arson attack on the train, which was planned through a video conference," The Daily Star newspaper quoted Harunor Rashid, Chief of Detective Branch (DB) of police and also the Additional Commissioner of Dhaka Metropolitan Police (DMP) as saying.

"At least 12-13 Jubo Dal unit leaders including Mansur held a video conference on Thursday around 6:00 pm.

They planned arson attacks in Kishorganj-Narsingdi and Narayanganj-Kamalapur routes and crude bomb attacks at various polling centres in different wards," Harun told a press conference at the DMP media centre.

The Daily Star also said, quoting the DB chief Harun that police have recovered clips of the video conference.

"One of them agreed to execute the arson attack on the train. Nabi was not present at the video conference, but was one of the financiers and advisors of the attack," he said.

The DB chief identified the other six arrested and said, "The planners engaged known criminals for the arson attack. Detectives got their names and were trying to arrest them."

However, demanding a UN-supervised investigation into the incident, the BNP, led by former prime minister Khalida Zia, called it a 'pre-planned' act of sabotage ahead of Sunday's general elections, which the party has boycotted and given a call for a 48-hour nationwide strike starting at 6:00 am Saturday.

In a statement, BNP senior Joint Secretary Ruhul Kabir Rizvi expressed concern over the heartbreaking incident of casualties due to arson by miscreants on the Benapole Express train.

"There is no doubt that the Benapole Express train fire was an act of sabotage, leading to the loss of life," The Daily Star newspaper quoted Rizvi as saying and further said that the BNP leader called for a UN-supervised investigation into the incident.

Meanwhile, the Dhaka Tribune newspaper reported that the Bangladesh Railways has formed a seven-member committee to investigate the incident, to identify the reason behind it and to fix responsibility.

Of the four, three coaches were completely burnt.

Railway officials said that most of the train's nearly 292 passengers were returning home from India.

Prime Minister Sheikh Hasina expressed deep shock and sorrow at the loss of four lives and directed the authorities concerned to investigate whether the fire was an act of sabotage.

More than 100 foreign observers, including three from India, have reached Dhaka to monitor the general election, polling for which begins at 8:00 am on Sunday.

Led by former prime minister Khalida Zia, the BNP is boycotting the general election as it wanted an interim non-party neutral government to hold the election, a demand rejected by the government headed by Hasina, also the head of the ruling Awami League (AL) party.

In the run-up to the January elections, Bangladesh witnessed a couple of train-related arson incidents among several incidents of violence in recent months.

On January 2, a train carrying some 300 passengers narrowly averted a major crash at the last minute as suspected saboteurs removed 28 dog spikes or hooks from the tracks on a railway bridge in northern Bangladesh.

An unidentified person on December 19 set a train ablaze killing four people, among them a mother and child, amid an opposition called countrywide strike on that day.

Earlier in the month, one passenger was killed and dozens wounded as saboteurs uprooted railway tracks when seven carriages derailed in Gazipur on the outskirts of the capital.

Awami League accused the BNP of carrying out the sabotage, which the party denied.