A route-6 bus was set on fire at Gulistan and another route-14 bus at Mohakhali on Tuesday evening.
An hour before the arson attacks, police arrested Fakhrul in front of the National Press Club.
Four vehicles were also torched in Dhaka until the afternoon during a countrywide transport blockade called by BNP Chairperson Khaleda Zia.
No casualties in the arson attacks were reported but the arsonists could not be identified.
Miscreants torched a bus at Old Dhaka's Tantibazar around 1:50pm.
Fifteen minutes later, a bus and a car were set on fire at Dhaka's commercial hub Motijheel.
Fire Service Control Room operator Nazma Akter said that three fire-fighting units rushed to Tantibazar and put out the fire.
The driver of the bus, ‘Masum’ said that five to six men boarded the vehicle from Gulistan.
"As soon as we arrived at Tantibazar they told me to stop.”
He saw fire at the back of the bus after the men had got off.
"I suspect those men set the bus on fire."
At 2:05pm, a state-owned BRTC bus was torched at Motijheel, said fire service official Naznin Sultana.
bdnews24.com's photojournalist Tanvir Ahammed reported from the scene that a car was also set ablaze at that time.
Witnesses said four to five men torched the vehicles and fled immediately.
Fire Service control room official Mohammad Ali said miscreants set a Gulistan-Mirpur route bus on fire at Shahbagh around 4pm.
Witnesses said two youths got off the bus at Shahbagh intersection and hurled a petrol bomb at it.
Fire-fighters doused the fire but the bus was badly burned.