HELSINKI—A Finnish air force pilot was killed Wednesday when his trainer jet collided with another Hawk during a training flight, the defense forces said.

One pilot ejected successfully and was treated for non-life threatening injuries at a hospital, officials said. It was not clear if the other pilot, whose body was found after a search of several hours, had used his ejector seat.

The defense forces said it had begun an investigation of the accident. It occurred over a sparsely populated area in western Finland in good weather above the clouds at a height of 1,500 meters (5,000 feet).

The dead man, a 30-year-old flight captain, was an experienced pilot trainer, the air force said.