President Biden is considering appointing Matthew Rojansky, head of the Wilson Center's Kennan Institute, as Russia director on the National Security Council, according to a source familiar with the situation.

Why it matters: Rojansky has been praised for his scholarship on Russia and is frequently cited in U.S. media for his expert commentary. But his work has drawn criticism — including in a 2018 open letter from Ukrainian alumni of Kennan that blasted the think tank he runs as an "unwitting tool of Russia’s political interference."

The simmering conflict in Eastern Ukraine has threatened to boil over the past few days, with Russia massing troops near the border and pro-Kremlin media raising the specter of war.

Why it matters: U.S. European Command went into high alert in light of the Russian movements, which some experts speculated could presage an active Russian military intervention in the Donbas region of Eastern Ukraine, where Ukraine has been fighting pro-Russian separatists for seven years.

Vladimir Putin has signed a law that would let him seek additional presidential terms in 2024 and 2030, Reuters reports.

Why it matters: Putin was running up against term limits until proposed constitutional changes were approved via referendum last year. Now he could potentially remain in power until 2036, when he'll be 83.

Go deeper: 20 Years of Putin — from KGB to Kremlin

Ukraine said Saturday that joint military exercises with NATO troops may begin in a few months, Reuters reports.

Why it matters: Russia, which supports separatist forces battling Ukraine's military in the Donbass region, said Friday it strongly opposes the drills and will "have to take additional measures" if NATO deploys troops to eastern Ukraine.

A Russian court on Friday found Twitter guilty of three counts of violating regulations on restricting unlawful content and fined the company 8.9 million rubles (about $117,000) for not removing posts that encouraged minors to take part in unauthorized protests, according to AP.

Why it matters: The fine comes amid a broad crackdown on the social media company in the country. In March, Russian authorities threatened to ban the platform entirely if the company did not remove some 3,000 posts containing content the government had deemed illegal.

President Biden spoke with Ukrainian President Volodymyr Zelensky on Friday for the first time since taking office, as U.S. and NATO officials warn of a Russian military buildup near eastern Ukraine that could ignite the long-simmering conflict, according to the White House.

Why it matters: It took more than two months for Biden to speak directly with the president of Ukraine, a key frontline partner in eastern Europe that has been pleading for more help from the West in its fight against Russian aggression.

Secretary of State Antony Blinken spoke with Ukrainian Foreign Minister Dmytro Kuleba on Wednesday to affirm the United States’ "unwavering support" for Kyiv amid a rise of Russian-backed separatist aggression in eastern Ukraine.

Driving the news: The war in eastern Ukraine, ongoing since 2014, escalated after the Ukrainian military said four of its soldiers were killed during a battle against Russian-backed separatists on March 26, the New York Times reports.

Russian opposition leader Alexei Navalny has gone on a hunger strike in prison in protest of authorities allegedly denying him medical treatment for pain and numbness in his back and leg, his Instagram account announced Wednesday.

Why it matters: Navalny's lawyers fear that his health is deteriorating in the remote Russian penal colony where he is serving a 2.5-year sentence. He wrote on Instagram that he is being "tortured by sleep deprivation" and has "no other methods of fighting," according to a Meduza translation.

When an authoritarian regime is being buffeted by Western sanctions, it can typically expect a helping hand from a powerful friend: Vladimir Putin.

Driving the news: As Myanmar's military was firing on protesters and bystanders on Saturday and the U.S. was preparing its toughest response yet to the Feb. 1 military coup, Russia's deputy defense minister was in Myanmar to show Moscow's steadfast support and desire to deepen its "strategic partnership."

Lawyers for Russian opposition leader Alexei Navalny said Wednesday that they fear his health is deteriorating in prison and that they were denied access by prison authorities when they arrived for a scheduled visit, ABC News reports.

Why it matters: Navalny's supporters fear that new attempts could be made to assassinate him while he is in prison, per ABC News.