"The Ukrainian side will do everything possible to ensure urgent, comprehensive and impartial investigation into this crime in order to bring those responsible to account," the statement said.
The ministry also expressed condolences to the family of the killed OSCE mission’s member.
Earlier in the day, law enforcement officials of the self-proclaimed Luhansk People's Republic (LPR) said an explosion of the observers' car occurred near Pryshyb settlement in the Luhansk region and, as a result, one SMM member was killed. According to the OSCE, two other observers were injured.
Anton Gerashchenko, an adviser to the Ukrainian Interior Minister Arsen Avakov, said earlier in the day that the blast had left a UK citizen killed and a German citizen injured.
