The bombing took place around 6:30am on Friday near Matribhuiyan on the Feni-Noakhali Highway.
The victims, Mohammad Yususf, 55, Mohammad Wasim, 26, Rabiul Islam, 16, 'Rokon', 24 and Abul Hossain, 49, loaded fish at Nimsar, in Comilla, and were heading to Noakhali’s Basurhat when five to six agitators threw two firebombs at their vehicle, Rokon and Rabiul told journalists at that Feni Sadar Hospital.
The hospital doctor AKM Foyez Akbar said, three of the victims - driver Yusuf, Wasin and Hossain - were severely burned and had been sent to the Comilla Medical College Hospital.
Dagonbhuiyan Police OC Abul Faisal said they had seized the burned pick-up truck.
The BNP-led 20-party alliance has been enforcing an indefinite transport blockade since Jan 5 along with sporadic shutdowns.
Although, the two-and-a-half-month agitation has had little impact on city life, the transport sector has been badly affected by repeated acts of violence.
The agitation has been marked by numerous bombing, vandalism, firebombing, and arson attacks on vehicles and properties, claiming at least 125 lives.