This is Russia’s key position on which it bases everything, Lavrov said in a wide-ranging interview broadcast on state television, adding the risks now are considerable.

"I would not want to elevate those risks artificially. Many would like that. The danger is serious, real. And we must not underestimate it," said Lavrov. 

He also said that the core of any agreement to end the conflict in Ukraine would depend largely on the military situation on the ground.