Investigators from Germany and Spain will join the Lithuanian authorities to find out what caused a DHL plane crash in Vilnius, Laurynas Naujokaitis, director of Lithuanian Justice Ministry's Transport Accident and Incident Investigation Division, said on Monday.

"We have information that the German safety authority has appointed four investigators to carry out the safety investigation, and they are currently on their way to Lithuania," Naujokaitis said, cited by the Baltic News Service (BNS).

Spain has also decided to send two experts for the investigation, he added, noting that they are also on their way to Lithuania.

Naujokaitis stressed that the investigation would focus solely on aviation safety and the probe could take at least a year.

According to the director, the U.S. aviation administration has also been informed of the crash as the plane was manufactured in the United States.

The Boeing 737-476 (SF) plane was owned by Spanish airline Swift Air. While flying from Leipzig, Germany, on behalf of German shipping company DHL, it crashed into a residential building near the Vilnius airport. A pilot was killed, and three others were injured in the incident.