Around four US soldiers were killed when a US airliner crashed during a NATO military exercise in Norway, killing at least four people, officials said. A total of 30,000 troops, 200 aircraft and 50 ships from member countries are taking part in the military exercises, which will continue until April 1. During the exercise, a US warplane crashed and caught fire. Four U.S. military personnel were on board the plane, which was killed on the spot. The cause of the accident could not be ascertained. However, strong winds were blowing and it was raining during the flight. This could be the cause of the accident but an inquiry committee has been formed to investigate.