KYIV, Ukraine – A passenger plane skidded past the landing strip and overturned in the eastern Ukrainian city of Donetsk on Wednesday, killing four people, injuring two and leaving the fate of two others unknown, officials said.

The small, Soviet-designed AN-24 plane was carrying 45 people from the Black Sea port of Odesa.

It was not immediately clear what caused the crash-landing, Emergency Situations Ministry spokeswoman Inna Sedova told the Associated Press.

The plane was operated by the small Southern Airlines company, which runs domestic flights out of Odesa.

Sedova said that four people have been confirmed dead, two were injured and the fate of two others remains unknown.

Donetsk Governor Andrei Shishatsky said that rescuers had located one of the missing people in the wreckage of the plane but were still unsure whether the person was alive, the Interfax news agency reported.

In recent years, former Soviet republics have had some of the world’s worst air traffic safety records.

Experts blame the poor safety record on the age of the aircraft, weak government controls, poor pilot training and a cost-cutting mentality.