Moscow has objected to plans by the Ukrainian army to conduct missile tests in the disputed region of Crimea, deepening the political crisis between the two nations. Russia annexed Crimea in 2014 sparking a worldwide diplomatic crisis.
The spat is particularly pertinent this weekend as a sombre Ukraine commemorates the victims of Holodomor, or the Terror-Famine, which took place in 1932-1933, on Saturday, 26 November. Ukrainians and academics believe the famine was a genocide committed by the Soviet Union. Russia denies this, saying citizens died as part of a widespread famine that engulfed the entire country.
On the same day Russia's aviation agency, Rosaviatsia, said its neighbour had notified them of the planned tests which were taking place near "Russia's sovereign air space".
The Russian defence ministry said the tests, due to take place on 1 and 2 December in the Simferopol area on Crimea's west coast, "violated territorial seas of the Russian Federation".
In a response, Ukraine's National Security and Defence Council Secretary, Oleksandr Turchynov, said: "Ukraine carries out the missile tests within the framework of all the international obligations and treaties. That's why we ask Russia not to hinder the tests by its hysterics and provocations."
Turchynov added that the nation was free to conduct military tests anywhere within its airspace, including Crimea. The planned tests, he said, would not be taking place near the Kerch Strait, which once separated Russia and Ukrainian-governed Crimea before the annexation.
Russia took over the region in March 2014 and held a highly controversial referendum which led to a vote by citizens to join Russia. Western nations then imposed sanctions against leading Russian companies in defence of Ukraine.
Ukraine has repeatedly expressed their objection to "Russian aggression" and on Thursday, 24 November, Ukrainian President Petro Poroshenko met senior EU officials Donald Tusk and Jean-Claude Juncker to encourage them to extend sanctions against Russia that were imposed after a Malaysia Airlines flight was shot down over Ukraine in 2014.
On Saturday, Poroshenko attended a memorial for those who died in the Holodomor. Although an exact estimate is not clear historians believe that around four million people died of starvation - approximately 24 Ukrainians every minute in the peak months of the famine.