Most likely, the car tripped a mine near the village of Pryshyb in the Luhansk region, Censor.NET reports citing the press service of the ATO Headquarters.
The OSCE SMM confirmed on Twitter that a patrol consisting of six patrol members and two armored vehicles has been involved in a serious incident.
''The patrol was driving in the vicinity of the village of Pryshyb, an area not controlled by the government in Luhansk region. As a result of this incident, one patrol member has died and two members have been taken to hospital for further examination,'' the statement reads.
OSCE Chairperson-in-Office, Austria's Foreign Minister Sebastian Kurz wrote on Twitter that responsible will be held accountable.
''Tragic news from Ukraine: SMM patrol drove on mine. One OSCE patrol member killed, one injured. Heartfelt condolences to family of victim and SMM team. Death of colleague is a shock to whole OSCE. Hope injured monitor will recover soon,'' Kurz wrote.