Sources said the blast rocked the entire terminal as it ripped through the coach of Hanif Enterprise at around 2:10pm, sending people scurrying for cover.

The bus was scheduled to leave at 2:30pm. Police said passengers of the bus were at the waiting room when the bomb went off.

Two people identified as Babar, 30, and Alam, 24, received shrapnel injuries. The explosion also damaged another bus of Eagle Paribahan.

Eyewitness account of the incident said the explosion occurred a short while after a man was seen getting down from the bus. Some said he had left a handbag inside the vehicle before disappearing into the terminal crowd.

"It was a time bomb," said Nasir Ahmed, officer-in-charge of Sonadanga Police Station, although Deputy Commissioner (South) Akbar Ali refused to comment before investigation.

Sources said the bomb was planted under seats H-1 and H-2. The tickets for these two seats were sold to businessmen Abdul Jalil and Tofazzal Hossain.

Security at the terminal has been beefed up and no-one is being allowed inside without having their luggage checked.