According to the current OSCE chairman, Sebastian Kurz, the car exploded due to a mine on its way. According to the LPR, the car deviated from the route it was supposed to follow. Later, the LPR's head urged the OSCE to coordinate routes its monitors' cars are chosing to avoid similar incidents.
The Russian Foreign Ministry also said that the "provocation" may be aimed to undermine the Ukrainian peace settlement.
"The circumstances of the incident indicate a high probability of a provocation aimed at undermining the peaceful settlement process in Donbass. It is obvious that such incidents and an escalation of tensions are beneficial for those who are not interested in implementing the political, economic and humanitarian provisions of the Minsk agreements, the Russian Foreign Ministry said in a statement posted on its website.
"We are outraged over this cynical action, which caused the death of a person and targeted international monitors who work for the sake of peace. We call for a thorough and impartial investigation and want the perpetrators to be brought to justice," the Russian Foreign Ministry added.
Moscow called for the facilitation of direct talks between Kiev and the self-proclaimed republics of Donetsk and Lugansk.
"We once again call for the intensification of direct negotiations between the parties to the conflict — Kiev, Donetsk and Lugansk — within the Contact Group to fully implement the [Minsk deal's] "Set of Measures" which is a basis for the settlement in the Donbass without any other alternatives."
A US medical company's staff member was killed in the OSCE SMM car blast, the ministry said.
"According to the OSCE, a car of the Special Monitoring Mission of the OSCE, returning from patrolling, was blown up by a land mine in Slovyanoserbsk area of Lugansk region in Ukraine, two kilometers from the contact line today in the morning. A US citizen, a staff member of a medical company working for the OSCE in line with a contract, was killed. The international observers in the car were injured. The Russian Foreign Ministry expresses condolences to the relatives of the victim and wishes fast recovery to those wounded," the statement said.
Eastern Ukraine has been in turmoil since April 2014, when the government in Kiev launched a military offensive against militia in Donbass. Despite the Minsk peace agreements signed in February 2015, the sides continue to blame each other for ceasefire violations.
The OSCE SMM to Ukraine was deployed in March 2014 to observe and report on the situation in the country.
This March, the SMM spokesperson told Sputnik that the observers of the OSCE Special Monitoring Mission (SMM) on Ukraine had been shelled at least seven times since the beginning of the year.