Russian Foreign Minister Sergey Lavrov said on Friday that the West needed to learn the “right lesson” from the Ukraine crisis, as he criticized efforts to contain Russia since the collapse of the USSR.

“If the goal is to prevent such crises from repeating in the future, the right lesson must be learned from events in Ukraine,” Lavrov told a security conference in Moscow.

The Ukraine crisis is “the logical result of the evolution of the situation in Europe in the last 25 years,” he said in reference to the 1989 fall of the Berlin Wall and subsequent collapse of the Soviet Union.

“Instead of seizing a historic chance to build a greater Europe without dividing lines, our Western partners preferred their usual logic aimed at extending the geopolitical space under their control to the east,” he said, calling this a “softer form of the Russian containment policy” of the Cold War.

Lavrov also said “foreigners speaking English” were among government troops battling pro-Moscow rebels in eastern Ukraine.

Russia’s chief of general staff, Valery Gerasimov, told the conference that military contractors were operating on Kiev’s behalf in the conflict.

“There is evidence of private military firms participating in the events in Ukraine,” he said, providing no further details.

Russia’s Interfax news agency quoted an anonymous source in the general staff saying: “According to our information, dozens of foreign mercenaries, including Americans, are taking part in military operations on the side of the Kiev authorities.”