A car drives past the headquarters of Yandex company, Russia's internet search engine, in Moscow on May 16, 2017. Ukraine on May 16 blocked Russia's most popular social media networks and an internet search engine in response to the Kremlin's alleged backing of a three-year separatist war in the east. (AFP/Natalia Kolesnikova)
Ukraine on Tuesday blocked Russia's most popular social media networks and an internet search engine in response to the Kremlin's alleged backing of a three-year separatist war in the east.
The decision sparked an immediate outcry from Ukrainian internet users and freedom of speech advocates.
Kremlin spokesman Dmitry Peskov called Ukrainian President Petro Poroshenko's decision "another manifestation of unfriendly, short-sighted policy toward Russia".
Some critics in Kiev further pointed to the irony of Poroshenko himself being an avid user of two of the Russian networks he had banned.
The pro-Western Ukrainian leader promised to quickly close his Russian accounts and defended the latest round of sanctions against Kiev's sworn foe as an "adequate response" to the Kremlin's "hybrid warfare" using the internet.
The presidential decree bars access to VK -- often referred to as Russia's Facebook and formerly known as VKontakte -- and Ukraine's version of the popular Yandex search engine.
The decision also covers the Mail.ru email provider and the Odnoklassniki (Classmates) social network.
The ban remains in effect for three years.
A senior eastern European analyst with the Bellingcat investigative research network said the VK ban would be especially painful for the Russian speakers who are trying to eke out an existence in Ukraine's impoverished eastern war zone.
"VK is used extremely heavily by civilians who live in the (east) to collect information, know where humanitarian aid is, talk to relatives," Bellingcat's Aric Toler wrote on Twitter.
"VK is also by far the best way for people to share witness accounts for what happens on the frontlines, with detailed timelines. That's gone."
A January 2016 ranking conducted by the Kiev-based Genius business consulting company placed VK and Mail.ru as the second and third most popular Ukrainian websites after Google.
VK said it had 16 million monthly users in Ukraine.
"We have always steered clear of politics," it said in a statement. "We believe that in its very essence, the internet has no borders."
More Russians banned
Kiev has been gradually expanding its list of outlawed Russian products and people barred from entering the country for either voicing support of the Kremlin's March 2014 annexation of Crimea or the self-proclaimed independence of Ukraine's east.
Numerous Russian television series and movies have been thrown off the airwaves and the silver screen. Ukraine has also blocked the import and sale of some books.
The West strongly supports Kiev's assertion that Russia has both plotted and backed the revolt in the eastern Lugansk and Donetsk industrial regions that has claimed more than 10,000 lives.
The war began less than two months after massive pro-EU street protests toppled a Kremlin-backed president in February 2014.
Both Kiev and the West see the conflict as Russia's retribution for the loss of its ally.
But human rights groups have criticized Ukraine's decision to apply its sanctions against various forms of cultural entertainment as a violation of free speech.
VK was used by "Ukrainian individual entrepreneurs who had pages and advertised their goods," Ukraine's Reporters Without Borders representative Oksana Romanyuk wrote on Facebook.
"And this is not to mention the millions of citizens who used it to have a social life," she wrote.
Poroshenko on Tuesday also expanded the number of Russian citizens and Kremlin supporters from other countries who can no longer enter Ukraine to 1,228 from 682.
The sanctions already in place nearly overshadowed the Eurovision Song Contest extravaganza that concluded this weekend with the victory of Portuguese crooner Salvador Sobral.
Ukraine banned Russia's contestant for having staged a performance in Crimea a year after its annexation.
Russia responded by deciding not to air the kitschy contest and organizers have warned Ukraine that it may be forbidden from taking part in upcoming events over its actions.