What's Russia's problem with Ukraine joining NATO?

Tensions between Russia and the West have been growing ever since Vladimir Putin started his proxy war in eastern Ukraine.

In response, NATO sent reinforcements to countries seen as vulnerable to Russian aggression.

In December, Moscow set out its security demands in two documents: a proposed treaty with the US, and an agreement with NATO.

Essentially, Russia now wants guarantees that NATO will halt its eastward expansion, rule out membership for Ukraine.

NATO leaders promised future membership to Ukraine and Georgia back in 2008.

Some experts put Russia's intentions in starker terms. For historian Françoise Thom, a specialist on Russia, Moscow's demands amount to "an orchestrated blackmail".

Source: EuroNews