The injured are Nasima Akhtar, 28, and Morsheda Begum, 14, who worked as maids at the mess belonging to one Mohammad Iqbal. Mainly garments workers and some bachelors reside in the mess at Kuri Pukurpar.

Witnesses and police said the incident took place at around 10:00am when the two maids were cooking in the kitchen.

"Suddenly, I saw that an object, which was thrown from the nearby graveyard, landed on the kitchen floor and exploded with a bang. As smoke began to fill the room, I fell unconscious," said Nasima, who received injuries in her hands, legs and face.

But she could not say why the bomb was thrown and who were the targets.

Nasima is now undergoing treatment at Chittagong Medical College Hospital while Morsheda, who was slightly injured, received first aid treatment.

Bandar police took Morsheda to the police station for interrogation.

A team of Rapid Action Battalion (Rab) seized the parts of the bomb and hundreds of pieces of spikes from the spot.