MOSCOW, May 14. /ITAR-TASS/. Russian Foreign Minister Sergei Lavrov called for investigating the use by Kiev of helicopters with UN markings during the security operation in the South-East of Ukraine.

He believes that Ukraine has come as close to civil war as never before.

Russia wants to understand how helicopters with UN markings were used against protesters in the South-East, Lavrov told Bloomberg on Wednesday, May 14.

Russia has suspicions that mercenaries from the United States are acting in the South-East of Ukraine.

United Nations examines recent media reports that helicopters with UN identification marks have been involved in the Ukrainian military operation near Kramatorsk.

If it is confirmed, it would mean that Kiev authorities violated agreements concluded with international organization. 

Earlier media reported that at least three helicopters colored white with UN identification marks were used in military operation near Kramatorsk.

There were three combat Mi-24 and one Mi-8 helicopters. Ukrainian helicopters were involved in several UN peacekeeping missions particularly in the Democratic Republic of Congo.