The conflict in eastern Ukraine has been going on for seven years and has claimed the lives of thousands of people.
Relations between Russia and Ukraine have become increasingly tense after Ukraine stated that Russia had strengthened with thousands of troops near Ukraine's borders.
Russia will keep military troops near Ukraine's border for as long as necessary, the Kremlin said on Wednesday.
SVT's Russia correspondent Bert Sundström says in Aktuellt that the escalation is very serious but that it is also difficult to interpret what it means.
- That Russia in some way tries to show muscle against Ukraine is obvious and that Ukraine feels strongly threatened is also obvious.
But it is not at all certain that Russia has plans to officially enter the military in eastern Ukraine, says Bert Sundström.
Why is this happening right now?
- It is difficult to assess, but possibly it is due to the Kremlin feeling a little insecure, that support for President Putin is not as stable as it usually is.
There are parliamentary elections in September this year and the Kremlin really wants the United Russia ruling party to take an overwhelming victory, and it looks doubtful right now because many are dissatisfied.
In addition, there is a feeling that the opposition politician Alekej Navalny can do something about it even though he is imprisoned.