Friday’s fire broke out at about 9pm (1500 GMT), injuring eight passengers as it spread to four compartments of the Benapole Express headed for the capital, Dhaka, at a time when the main opposition party is boycotting the elections.

“The timing of this tragedy, just a day before the election … shows an absolute intention to hinder the festivity, safety and security of the democratic processes of the country,” Foreign Minister A K Abdul Momen said.

“This reprehensible incident, undoubtedly orchestrated by those with malicious intent, strikes at the very heart of our democratic values,” he added in a statement, vowing that authorities would bring the perpetrators to justice.

The main opposition Bangladesh Nationalist Party (BNP) has asked people in the South Asian nation to shun the poll and called a two-day strike nationwide from Saturday.

The eight people critically injured in the blaze are being treated in hospital, officials said.

“All eight, including two children, have burnt their respiratory tracts,” said Dr Samanta Lal Sen of a state-run specialist burn hospital in the capital.

“We are closely monitoring them,” he told reporters.

Seven firefighting teams took an hour to subdue the fire in Dhaka’s area of Wari, fire official Shahjahan Sikder said.

Second boycott in three elections

The poll boycott by the main opposition Bangladesh Nationalist Party (BNP) is its second in three elections. The party says Prime Minister Sheikh Hasina’s Awami League is trying to legitimise a sham vote to gain a fourth straight term.

Hasina, who has refused BNP demands to resign and cede power to a neutral authority to run the election, accuses the opposition of instigating anti-government protests that have rocked Dhaka since late October and killed at least 10 people.

A senior BNP official, Ruhul Kabir Rizvi, said Friday’s express train fire was “undoubtedly an act of sabotage and cruelty”, while blaming the ruling party for it.

Four people died last month in a train blaze set by protesters during a countrywide strike called by the opposition.

On Saturday, Dhaka’s usually busy roads were largely deserted, although security forces patrolled in armoured vehicles.

About 800,000 security officials will guard polling booths on Sunday, while some of the armed forces have fanned out nationwide to help keep the peace.

Police said unidentified arsonists also set fire to at least five primary schools, including four polling booths.

They are investigating fires in Gazipur, on the outskirts of Dhaka, suspected to have been set in the middle of the night by those aiming to disrupt Sunday’s election.

“We have intensified patrolling and remain on high alert,” said Gazipur police chief Kazi Shafiqul Alam.

Arsonists also attacked polling booths in the northeastern districts of Moulavibazar and Habiganj, police said, with similar incidents reported elsewhere in the past two days.

Police in the coastal district of Khulna arrested two people on Thursday night accused of trying to set fire to a school.

The following day, another bid to set fire to a primary school nearby was averted, said Saidur Rahman, police chief of the district.