This ends our live blogging for May 31. Be sure to check back tomorrow for our continuing coverage.
After Kyiv banned Russian social networks:
U.S. Senator Cory Booker is in Kyiv and he's been talking to RFE/RL's Ukrainian Service:
Interview: U.S. Senator Booker Says Russia Trying to Destabilize Democracies Globally
KYIV -- Russia's interference in Ukraine is just one sign of a broad attempt to destabilize democracies around the world, U.S. Senator Cory Booker (Democrat-New Jersey) has told RFE/RL.
"When it comes to Russian aggression, let's be clear: The Russians are seeking to not just attack Ukraine, or attack the U.S., they are trying to undermine democracy," Booker said in an interview with RFE/RL's Ukrainian Service in Kyiv on May 31.
"Their attempt is to create divisions and divisiveness between individual leaders as well as within nations. And that's unacceptable," said Booker, who is on the Senate Foreign Relations Committee.
Russia seized control of Crimea in March 2014 after sending in troops without insignia, engineering a takeover of the regional legislature, and staging a referendum that was swiftly dismissed as illegitimate by Ukraine, the United States, and a total of 100 countries at the UN General Assembly.
Moscow has portrayed its takeover of Crimea as necessary to protect ethnic Russians and other residents of the peninsula from oppression by pro-Western officials who came to power in Kyiv following the ouster of Russia-friendly Ukrainian President Viktor Yanukovych in February 2014.
That narrative has been rejected by Ukraine and Western governments, which accuse Russian-backed authorities in Crimea of rights abuses against Crimean Tatars and others opposed to Moscow's rule there.
Since 2014, the EU and United States have maintained sanctions on Russia over its seizure of Crimea and its actions in eastern Ukraine.
Booker, who has advocated increasing sanctions against Russia, said that he believes relations with Moscow need to be improved but added that "the question is not if, it's how."
"Putin is somebody who is not going to negotiate with you if he thinks you're weak. Right now we need to show our strength....We need to show our strength through unity with our allies," Booker said.
"You cannot appease people who are showing aggression without meeting them with strength," he said.
"This is not just a Ukrainian fight, this is a transatlantic fight," Booker added.