INTERNATIONAL: Ukraine has declared its independence after the Soviet Union collapsed in 1991. At the time, a substantial portion of the Soviet nuclear arsenal was housed within Ukraine's borders, and it agreed to transfer those weapons to Russia.

Some years later, Ukraine's democratically elected government has grown closer to Western Europe, even as cultural ties to Russia persist, especially in the nation's east.

Ukraine's ambassador to the United Nations, Pamela Falk says Putin's ambition is to "restore the Russian Empire" has moved beyond the annexation of Ukraine's Crimean Peninsula, which his forces seized in 2014.

Russian forces have invaded eastern Ukraine in 2014, and Putin has claimed the assault was merely a defense of ethnic Russians who live in Ukraine's eastern Donbas region, who've never supported the country's relatively new, pro-Western government.

But Putin has used the invasion to very literally claim part of Ukraine for Russia, unilaterally annexing the Crimean Peninsula. The annexation is not recognized by the international community, but Russia has indisputably controlled the territory since 2014.

Since the annexation, a proxy war has been waged in Donbas between Russian-backed forces and the Ukrainian government. A 2015 peace deal has largely ended the major battles, but the fighting has continued, and left more than 14,000 people dead in the process, according to the Ukrainian government.

On February 21, Putin has unilaterally recognized the independence of two breakaway regions in Donbas,the self-declared "People's Republics" of Donetsk and Luhansk. This move has led to the U.S. and its allies imposing new sanctions on Russia.