HELSINKI (Reuters) - Four people were killed and several injured when a train crashed into an army truck during a military exercise in southern Finland on Thursday, police and the armed forces said. The accident occurred at an unguarded railway crossing near the city of Raasepori, 90 km (56 miles) west of the capital Helsinki, when two military vehicles were crossing the tracks on their way to a training site. The train and one of the vehicles collided, killing three soldiers aboard the truck and a passenger on the train, officials said. Road conditions were bad in the morning due to rain and snowfall. Inspector Ilkka Kantola told Helsingin Sanomat newspaper that the train had hit the truck at a speed of around 100 kilometres per hour. According to Kantola, the train driver had seen the truck but thought that it would stop as it was driving very slowly.  The train put on the break but the speed did not necessarily slow down at all ahead of the collision,  Kantola was quoted as saying. The soldier who had driven the truck will face charges for endangering traffic safety and manslaughter, he added. Four people were taken to Helsinki with severe injuries and seven others were treated at a local hospital for minor injuries. All patients were said to be in stable condition. Finnish Prime Minister Juha Sipila and President Sauli Niinisto both offered their condolences to the victims and their families.  The young conscripts were there for their country. That their journey ends in many deaths and in serious injuries is a true tragedy,  President Niinisto said in a statement. Military service is obligatory for men in Finland. 