A similar bomb was recovered at Ruet main gate on Tuesday.

One of the bombs was wrapped in aluminium sheet and had a short erroneous message carved on it from "Jadid al Qaeda".

Police rushed to the scene soon after locals informed them around 9:00am. One bomb was found near the main gate while the other was recovered at a bus stop shed near the main gate.

A police bomb expert team led by Sub-inspector (SI) Alamgir Hossain defused the bombs.

The four-line message inscribed on the aluminium plate mentioned that there were six bombs in total in the area, sources said.

Rapid Action Battalion (Rab) and Special Branch of police cordoned the entire RUET campus off. They searched the area until 2:00pm but could not find any other devices, which were claimed to be present in the message.

"All the three bombs are similar and locally made, these were sufficient to cause large number of casualties," SI Alamgir told The Daily Star.

The same electric circuit, four pieces of IC (integrated circuits), four batteries, electric switches and explosives of Tuesday's bomb were used to make the bombs, described the bomb expert. More than 200 bicycle bearing balls, parts of barbed wire, pieces of glass were used as splinters in one bomb, he added.