ColomboNineteen people, including 12 Army and Air Force personnel, were injured in a pre-dawn explosion on a bus in Sri Lanka on Wednesday, the military said, without ruling out a terror angle.The explosion took place around 5:45 am when the bus was en route to the military base town of Diyathalawa from the northern peninsula of Jaffna, military spokesperson Brigadier Sumith Atapattu said.Seven army and five air force personnel besides seven civilians were injured in the incident, Atapattu said.The explosion occurred at Kahagolla area in Diyatalawa, local media quoted police as saying. The bus was heavily damaged and the injured were hospitalised.“The explosion cannot be ruled out as an act of terrorism as of yet. Nevertheless, a highly explosive substance inside the bus may have caused the explosion. The cause can be ruled out after the government analyst inspects the scene,” Atapattu was quoted as saying by Daily Mirror newspaper.A statement by the Army’s media unit said that police investigations were in progress.Sri Lanka saw a brutal civil war involving the Liberation Tigers of Tamil Eelam (LTTE) and had witnessed large scale violence during the 30-year-long separatist movement that claimed over 100,000 lives.Hundreds of security personnel were also killed in the fight till 2009, when the LTTE was finally crushed by the Lankan military with the death of its supremo Velupillai Prabhakaran. There have been hardly any reports of attacks on the military ever since.