"Right now we are seeing a deterioration of the situation" in eastern Ukraine, Putin said at a press conference with his Belarus counterpart Alexander Lukashenko in Moscow.

Russia has held massive military drills near Ukraine's borders in recent weeks.

But Putin, who has demanded promises from the West that NATO won't expand eastwards, said the drills -- involving tens of thousands of soldiers -- are not a threat.

"These exercises are purely defensive in nature and do not threaten anyone."

He said the West and its allies are "not yet inclined to look seriously at these key security demands."

Russia this week demanded that the US commit to pulling out all of its troops from Central and Eastern Europe.

The longtime Russian leader on Saturday will personally oversee military drills involving Moscow's "strategic forces" which will include ballistic and cruise missile launches.