Law and Order Minister Sagala Ratnayaka informed Parliament that the fire erupted in a bus at Diyatalawa, this morning, was due to a Grenade explosion. 

"It might have been in the bag of a passenger," Ratnayaka said. 

He said the law enforcement authorities were conducting further investigations into the incident. 

Nineteen passengers including twelve military personnel were injured in an explosion inside a bus in Diyatalawa this morning. 

seven soldiers and five airmen were among the military personnel who were injured. The rest of the injured were civilians.

Investigations are underway to ascertain whether the grenade was in the bag of a solider.