But was Putin really the provocateur in Sunday's naval clash outside Kerch Strait, the Black Sea gateway to the Sea of Azov?
First, a bit of history.
Western governments have rallied behind Kiev, accusing Russian Federation of illegally blocking access to the Sea of Azov, used by both countries, and of using force without justification.
Russia, meanwhile, insisted the Ukrainian vessels were in its territorial waters and refused to communicate with the Russian coast guard, or accept a Russian pilot to guide them through the narrow strait. The Kerch Strait connects the Sea of Azov with the Black Sea.
North Atlantic Treaty Organisation vessels passing into the shallow Sea of Azov has been a redline of sorts for Moscow, and doing so would be an incredibly bold and risky escalation. REUTERS/Alla Dmitrieva A Ukrainian sailor, second right, is escorted by Russian intelligence agency FSB officers from a court in Simferopol, Crimea, Wednesday, Nov. 28, 2018. In the video, the Russian sailors can be heard shouting "crush him" as the Russian vessel rams the Ukrainian tugboat. The Russians then captured the 24-member crew.
Speaking at a German-Ukrainian economic forum in Berlin later on November 29, German Chancellor Angela Merkel said she planned to press Putin at the G20 summit on November 30-December 1 this week to urge the release of the ships and crews.
For his part, Putin has sought to play the matter down, calling it a "border incident, nothing more".
Mr Poroshenko has low popularity ratings.
"We need to rebuff the aggressor at any moment", Poroshenko told troops, according to a statement on his website.
It has said the Ukrainians were violating Russian waters and that Ukraine did not inform Russian officials of its naval movements. Ukraine alleges that's effectively amounted to a blockade of its ports in that sea, with Russian Federation frequently stopping and searching its ships.
On Tuesday, he warned there was a threat of "full-scale war" with Russian Federation.
Why would he provoke the Russians?
Russia is calling on the United Nations, the OSCE, the Council of Europe and other worldwide organizations to pay attention to violations of human rights in that country, Russian Foreign Ministry spokesperson Maria Zakharova said on Friday.
Some Westerners want even more in the way of confronting Putin.
Why is control of the Kerch Strait any of our business?
The Russian military on Wednesday announced plans to deploy advanced antiaircraft missiles to the Crimean Peninsula amid rising tensions between Moscow and Kiev.
Russia's foreign ministry responded to the temporary ban on Friday, criticizing Ukraine leadership and saying it would not reciprocate. "We do not, nor will we ever, recognize Russia's purported annexation of Crimea".
Do the American people care a fig for these places? "If they had done something differently, they should have been put on trial for that".