Ukraine and its European allies have long accused Russia of having a military presence in eastern Ukraine.
NATO estimates some 1,000 Russian soldiers are helping separatist rebels. And it says Moscow is providing weapons and artillery; Russian president Vladimir Putin denies the accusation.
Putin says he is not trying to break Ukraine apart and insists the people of eastern Ukraine deserve more autonomy. But recent comments made by Putin suggest he may have something else in mind.
On Sunday he urged for talks on the issue and used the word 'statehood' for the first time in relation to eastern Ukraine. Remarks that Russia's presidential spokesman says were misinterpreted.
As NATO members contemplate a strong response to the crisis, we look at what Russia is trying to achieve in Ukraine? And NATO's potential involvement.
Presenter: Nick Clark
Pavel Felgenhauer - defence analyst and columnist with Novaya Gazetta.
Alexei Garan - professor of comparative politics at Kiev Moheela University.
Kadri Liik - senior policy fellow at the European Council on Foreign Relations.