Chattogram Metropolitan Police (CMP) have asked all its units across the city to remain alert following the explosion inside a traffic police box in the city's Sholoshahar Gate-2 area last night.

"We have asked all units of police in the city to remain alert," Amena Begum, additional commissioner (administration) of the CMP, said while talking to reporters at her office this noon.

CMP also issued alert at the important establishments of police and the government in the port city following last night's incident, said the police official.

Meanwhile, an 11-member team of Anti-Terrorism Unit of Dhaka police reached Chattogram this morning, and along with the CMP's bomb disposal unit, collected evidences from the spot, said Amena Begum.

Two policemen and a pedestrian were injured in an explosion inside a traffic police box in Chattogram's Sholoshahar Gate-2 area around 9:30pm last night.

Traffic Sergeant Arafat Hossain had his face burnt in the blast while the two others suffered minor injuries

Visiting the area around 11:00pm yesterday, The Daily Star found the traffic police box was badly damaged in the explosion.

Officials of a bomb disposal unit of the CMP suspected that it was an explosion of an improvised explosive device.