Ukraine’s Parliament voted Monday to declare martial law in areas bordering Russia, responding to an attack a day earlier by Russian forces who fired on and impounded three Ukrainian naval vessels, leaving several sailors wounded.
The action by Parliament, which called it a “partial mobilization,” takes effect Wednesday morning, will last for 30 days and represents a further escalation of tensions between Russia and Ukraine.
President Petro O. Poroshenko of Ukraine had requested the vote, which happened as criticism of Russia was rising at the United Nations Security Council and NATO over the Sunday attack.
Nikki R. Haley, the ambassador from the United States, called the episode an “arrogant act” b y Russia that the Trump administration and the international community would not accept.
“As President Trump said many times, the United States would welcome a normal relationship with Russia, but outlaw actions like this one continue to make that impossible,” she said.
And Britain’s ambassador, Jonathan Allen, warned that the confrontation could preside further efforts by Russia to gain full control of the waters it currently shares with Ukraine.
The Ukrainians also received a strong statement of solidarity from NATO’s secretary General, Jens Stoltenberg, who said at a news conference in Brussels that all of the organization’s members “expressed full support for Ukraine’s territorial integrity and sovereignty.” He called on Russia to ensure “freedom of navigation” for Ukraine and demanded that Russia “release immediately the Ukrainian sailors and ships it seized. “
Russia has said it was forced to open fire after the Ukrainian ships entered what the Kremlin called Russian territorial waters,
At the United Nations on Monday, the Russian delegation tried to convene an emergency session of the Security Council that would have condemned Ukrainian aggression, but was blocked by other members of the council.  Russia’s representative, Dmitry Polyansky, lashed out at Ukraine, accusing its leaders of fostering hatred of Russia through brainwashing, and suggested that confrontation with Russia was advantageous for Mr. Poroshenko, who is behind in the polls ahead of elections in March.
In Ukraine’s ambassador, Volodymyr Yelchenko, warned that the clash at sea could make way for further incursions into Ukrainian territory by Russian forces. Ukraine has two major ports on the Azov Sea, Mariupol and Berdyansk, which depend on the free movement of ships through the Kerch Strait.
The violence occurred close to the 79th anniversary of the Soviet Union’s war with Finland in 1939 , a fact that Mr. Yelchenko said was no coincidence.
“What is happening today in the Azov Sea is reminiscent of the events of the 1930s,” he said.