MOSCOW, April 23. /ITAR-TASS/. Russia insists on investigation of reports on involvement of the U.S. private military organization Greystone in the current events in Ukraine, Russian Foreign Minister Sergei Lavrov said Wednesday in an interview with the Russia Today television channel.

He said the military observers dispatched to Ukraine by the Organization for Security and Cooperation in Europe (OSCE) had admitted the absence of any evidence of the presence of Russian military observers in eastern Ukraine. They noted only a possibility of the presence there of some kind of military advisers but he said they should continue watching the situation to understand the situation better.

“The only fact the Americans made references to was that the fighters (in eastern Ukraine - Itar-Tass) was the people there were using the weapons of Russian manufacture but everyone in Ukraine uses Russian weaponry, for instance the Kalashnikov assault rifle or the Makarov handgun,” Lavrov said. “This means a proof of this sort can scarcely be called sufficient.”

He also said reports had come several days ago on discovery of a cache with U.S. weaponry in Ukraine, adding: “This should necessarily be investigated.”

Lavrov recalled that the Russian side had raised the problem during contacts with U.S. counterparts.

“Some reports said several hundred specialists from the private military company Greystone had arrived Ukraine from the U.S.,” he said. “Also, reports said foreigners had been involved in several accidents.”

“Americans told us they didn’t have any information on this and then they said they had referred the question directly to Greystone and the organization had denied any involvement on its part.’

“Still we’d like to know who is doing certain things because there are too many deflections of reality otherwise if you use the language of diplomacy,” Lavrov said.