The clash occurred at the Picture Palace Cinema Hall Square where the KCC employees had gathered to form a human chain as part of a protest against Sunday's grenade attack on the mayor's car.

Eyewitnesses said an on-duty traffic constable was assaulted by some agitated KCC employees after police prevented them from gathering at the spot. Following this, a large contingent of police from Khulna Police Station rushed to the spot at around 9:50am and baton-charged protesters. The police and demonstrators fought a pitched battle for 40 minutes.

Officer-in-Charge (OC) Mosharraf Hossain, Sub-inspector Faruque, Sergeant Mosharef Hossain, Assistant Sub-inspector Koushik and three constables of Khulna Police Station were among the injured.

Thirteen were admitted to Khulna General Hospital with serious injuries.

Several cars and rickshaws were damaged during the clash. OC Mosharraf Hossain said three blank shots had to be fired to disperse the crowd.

KCC Employees Union said the attack on them was unprovoked. The mayor also denounced the "unprovoked" attack and "police excesses" saying it was a ploy to divert people's attention from the grenade attack on him.

Acting Police Commissioner Sajjad Ali refuted the allegation saying his men exercised maximum restraint in the face of brickbats hurled by KCC employees who formed the human chain violating traffic rules.

The attack won't go unchallenged, leaders of KCC Employees' Union threatened, and demanded removal of policemen responsible for the mayhem.

Normal work at the KCC came to halt following the clash. The KMP withdrew all traffic posts from the city at 12:00 noon yesterday for unknown reasons.