MOSCOW (AP) — A member of the OSCE's arms monitoring mission in eastern Ukraine has died and two others have been wounded after their vehicle was blown up by a mine in the separatist Luhansk region.

Austrian Foreign Minister Sebastian Kurz, who holds the rotating chairmanship of the Organization for Security and Cooperation in Europe, called for an investigation into the Sunday blast. He said on Twitter that "those responsible will be held accountable."

Anton Gerashchenko, an adviser to Ukraine's Interior Ministry, said the man killed was a British citizen. The monitoring mission said two other members were injured.

The self-proclaimed security ministry for the Russia-backed separatist rebels in Luhansk said the mine had been laid by Ukrainian forces. The rebels and the Ukrainian government have been fighting in eastern Ukraine since 2014 in a war that has killed more than 9,900 people.