Sources in Lohagara fire service said there were three women and a child among the deceased.

Besides, six others sustained serious injuries.

However, the identities of the deceased could not be confirmed immediately. 

Witnesses say the driver of a Chattogram-bound speeding bus of Relax Paribahan lost control over the steering while trying to stop the bus with a 'hard brake' at a turn in the Chunti Jangalia area along the Chattogram-Cox’s Bazar highway. 

Meanwhile, a speeding microbus from the opposite direction rammed into the bus. 

Within seconds, another speeding microbus hit the previous one from the rear side leaving four people dead on the spot.