Ukraine's President Petro Poroshenko has warned that Russia will face serious consequences if it attacks its neighbor Ukraine, days after Russia seized three Ukrainian navy ships and their crew members claiming they had entered Russian waters illegally.

"We will fight for our freedom, we will fight for our democracy, we will fight for our soil," Petro Poroshenko told NBC News on Tuesday evening. "The Russians will pay a huge price if they attack us."

Ukraine and Russia's relationship hit a new low on Sunday after Russia seized three Ukrainian Navy vessels (two artillery ships and a tug boat) and their 23 crew members in the Kerch Strait, a channel that separates the Sea of Azov and Black Sea, to the south of Ukraine and Russia, on Sunday.

Ukraine said the incident was an "act of aggression," while Russia said the ships had entered its territorial waters illegally. Both sides accuse the other of violating the conditions of a 2003 treaty that enshrines free access to the Kerch Strait and Sea of Azov.

The latest episode marks yet another low point in relations between the neighbors after Russia annexed Crimea from Ukraine in 2014 and supported a pro-Russian uprising in east Ukraine in the same year – although the Kremlin denied any involvement. Needless to say, Russia's actions provoked international condemnation and a range of sanctions were imposed on it.

Ukraine's president has responded to the latest provocation by declaring martial law in certain parts of the country, namely areas which border Russia. He also warned that a land invasion by Russia was a threat.

Speaking to NBC's Richard Engels ahead of a Group of 20 (G-20) summit in Buenos Aires this weekend, where President Trump is expected to meet with Russian President Vladimir Putin, Poroshenko said he wants a message passed on to Putin:

"Please, get out from Ukraine, Mr. Putin," Poroshenko said.

To read the whole story from NBC News, click here.

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