MOSCOW — While you wouldn't think it given their current caustic relationship, Russia and Ukraine used to be friends much like the U.S. and Canada. That was before these former allies became embroiled in the long and painful divorce that is a conflict that has resulted in the deaths of around 8,000 people.
The latest tit-for-tat exchange came this week when Russia announced it would stop all Ukrainian commercial flights entering its airspace in retribution for a similar ban imposed by Kiev. NBC News' Moscow-based producer Alexey Eremenko explains nine ways the two countries went from having a cordial friendship to an all-out feud:
1. They've Stopped Visiting Each Other
When the mutual bans on commercial flights come into effect on October 25, trains will become the only regular connection between Russia and Ukraine.
This is a huge problem for the 2.5 million Ukrainians — mostly migrant workers — living in Russia. The restricted transit routes will make it harder for them to return to their homeland.
As if the airspace restriction were not enough, Russia is also building new railway lines so that trains traveling between different regions don't ever have to pass through Ukraine.
2. They've Stopped Trading With Each Other
While Russia remains Ukraine’s biggest trading partner. trade between the two countries shrank by 60 percent year-on-year in the first half of 2015, according to Russian Customs figures. It will likely get worse next year when Russian sanctions against Ukrainian foods come into effect.
Russia continues to supply natural gas to its angry neighbor, however. Moscow switched off the gas tap to Ukraine twice in the 2000s over price squabbles, but may be reluctant to do so again because this would cut off the supply to Europe, and with it hundreds of millions of customers in the European Union.
3. They've Stopped Making Missiles Together
In the Cold War era, factories produced complicated machinery all over the Soviet Union. Remnants of this survived after the fall of the Soviet state in 1991, and parts for Russian aircraft and missiles were until recently still produced in Ukraine.
In light of their frosty relations, Kiev has now stopped shipping engines and engine parts. Russia now has to manufacture missile components itself if it wants to keep them flying, a process that will take years and billions of dollars, according to experts.
4. They've Stopped Hitting the Beach Together
Ukrainian tourists until recently accounted for two-thirds of the 6 million people visiting Crimean resorts each year. Since the region was annexed by Russia, the inflow has dwindled to nothing and the peninsula sees only half the tourists it used to, according to regional officials. Webcam footage of empty beaches making the rounds on the Internet only underlines this point.
5. They've Stopped Sharing Films and Songs
Both Russia and Ukraine have vibrant — if not necessarily high-class — pop music scenes, and Ukraine used to be the second-biggest market for Russian artists.
But 14 top Russian musicians and performers were blacklisted in Ukraine in August for endorsing Crimea’s annexation. Russia imposed no such bans, but Ukrainian pop stars no longer perform there, largely for patriotic reasons.
Ukraine has also banned 160 recent Russian films and TV shows for fear of "aggressor propaganda."
Russian film stars have shown support for the rebels in Ukraine. Artist Mikhail Porechenkov — the star of a Russian remake of Arnold Schwarzenegger's 1985 classic "Commando" — has even been filmed last year firing a machine gun toward Ukrainian positions in Donetsk. He later said that “the shoot was staged and the rounds were blank.”
6. They've Stopped Being Geopolitical Friends
Ukraine traditionally tried to balance a pro-Western stance with a pro-Russian one.
The current crisis was preceded by riots in Kiev that were sparked because then-President Viktor Yanukovych, who was backed by Moscow, rejected a deal with the European Union in favor of stronger ties with Russia.
Now the country’s leadership is intent on joining NATO and one day the European Union.
Ukraine’s official military doctrine explicitly lists Russia as an enemy.
7.They've Stopped Being Polite at the U.N.
Even diplomatic courtesy has gone out of the window. At the ongoing 70th session of the U.N. General Assembly in New York, the Russian delegation walked out of Ukrainian President Petro Poroshenko’s speech. Poroshenko, in turn, walked out on Russian President Vladimir Putin’s address.
8. They've Started Battling Over Their Shared History
The heartlands of Russia and Ukraine used to be part of the same Slavic state of Kievan Rus for a period during the Middle Ages. Their relationship in emerging as separate nations has been more complex than the plot of "Game of Thrones" — and since their recent falling out they have begun vilifying each other by trying to lay stronger claims on aspects of this shared history.
A good example of this is the story of Prince Vladimir, who baptized Kievan Rus in the 10th century. The prince has a titanic monument in Kiev, his home seat. But now Moscow (founded a century after his death) is building its own gigantic Prince Vladimir statue in a non-so-subtle attempt to claim what used to be a shared past.
9. They've Stopped Giving Peace a Chance
The more trivial spats aside, nearly 8,000 people have died in the conflict in eastern Ukraine, according to the U.N.'s latest figures.
Russia has repeatedly denied deploying troops there, despite what the West and most analysts agree is growing evidence to the contrary. Moscow does admit that Russian volunteers are fighting in the region, many of whom were recent recruits.
More than 2 million Ukrainians have fled their homes — hundreds of thousands seeking refuge in Russia but mostly being displaced within their own country.
Ongoing violence and use of artillery make a mockery of a ceasefire brokered by European leaders in February.