At least four people have been killed and nine injured following an explosion targeting a government-owned bus in eastern Syria, according to the state news agency SANA.The explosive device detonated while the bus, belonging to the Syrian Ministry of Energy, was travelling on a highway connecting Deir Az Zor and al-Mayadin, SANA reported in a post on X on Thursday.Recommended Stories list of 3 itemsend of listAll four deaths were security personnel at an oil facility in Deir Az Zor, the country’s oil heartland and seventh largest city, which was the site of fierce battles against ISIL (ISIS) during the country’s ruinous civil war.Oil facility workers as well as civilians were among those who were injured in the attack, SANA added, without providing further details.A video verified by Al Jazeera from the site of the explosion showed several security personnel inspecting a bomb-damaged bus on the side of a road.According to the Reuters news agency, the security personnel were part of an army contingent securing the Teim oilfield. They were reportedly returning home after their shift at the oil facility when the explosion took place.The incident is said to be the deadliest explosion in the eastern province, which also produ …