The dead was identified as Mohammad Elias, 22, son of one Bachchu Mian.

Three of the injured -- Nur Nabi, Rubel and Belal -- were admitted to a local hospital in a critical condition.

According to sources, activists of Awami League and BCL were returning home by bus after attending road march programme of the AL-led 14-party combine held in the city's Alongkar intersection at around 2:30pm.

The activists were locked into an alteration with a truck driver as he was blocking the way of the bus carrying the AL and BCL men in front of Shah Waliullah Filling Station.

At one stage, the activists assaulted the driver, leading to a clash with local BNP men and transport workers, sources said.

During the clash, the BNP men beat up BCL activist Elias with iron rods and injured him critically. He succumbed to his injuries on the way to hospital.

Protesting the incident, angry activists of the BCL put up barricades on Dhaka-Chittagong highway, disrupting traffic movements for about three hours.

When contacted, Sub Inspector Abdul Latif of Sitakunda Police Station claimed that Elias died in a road accident.