Police are investigating the fires in Gazipur, on the outskirts of capital Dhaka, but suspected that wrongdoers aiming to disrupt Sunday's election had set fire to the schools in the middle of the night.
«We have intensified patrolling and remain on high alert to thwart any untoward incident,» said Gazipur police chief Kazi Shafiqul Alam.
The main opposition Bangladesh Nationalist Party (BNP), boycotting for the second time in three elections, says Prime Minister Sheikh Hasina's Awami League is trying to legitimise a sham vote that will deliver her party a fourth straight term.
Hasina, refusing BNP demands to resign and cede power to a neutral authority to run the election, accuses the opposition party of instigating anti-government protests that have rocked Dhaka since late October and killed at least 10 people in the South Asian country.
The BNP has asked citizens to shun the poll and called a two-day strike in the country from Saturday.
Roads in Dhaka, clogged with traffic on normal days, were largely deserted on Saturday, with security forces patrolling the city in armoured vehicles.
Arsonists attacked polling booths in the northeastern districts of Moulavibazar and Habiganj, police said, adding that similar incidents had been reported across the country over the past two days.
In the coastal district of Khulna, police arrested two people on Thursday night after local citizens caught them allegedly trying to set fire to a school.
Another attempt to set fire to a primary school building in the same area was averted by locals on Friday, said Saidur Rahman, Khulna's police chief.
«We are on alert and are on the lookout for the arsonists,» Rahman