In a harrowing episode of violence in Dhaka's diplomatic heartland, a policeman fired indiscriminately near the Embassy of Palestine in Baridhara, killing a colleague and injuring another person.

The incident erupted without warning around 11:45pm on Saturday when Constable Kausar Ahmed started shooting randomly at the guardroom on the north side of the embassy, said Mazharul Islam, chief of Gulshan Police Station.

Another constable, Monirul Islam, died instantly at the scene, Mazharul said.

A pedestrian named Sazzad Hossain Shahrukh, who works as a chauffeur at the Embassy of Japan, was injured as the enclave, usually serene and heavily guarded, turned into a scene of terror and confusion as shots echoed through the night.

Sazzad was admitted to the United Hospital in Gulshan.

Mazharul said the motive behind Kausar's sudden and inexplicable burst of violence appears to be a loss of control.

The Gulshan police chief confirmed Kausar has been disarmed and taken into police custody.