Updated January 23, 2022 at 12:41 PM ET

The situation along the Russia-Ukraine border remains tense, as Russia has amassed an estimated 100,000 troops just across the divide while Ukraine's outnumbered military prepares to defend itself against a possible invasion.

Adding to the turmoil, the British government revealed details on Saturday of what it called an alleged Russian plot to install a pro-Kremlin leader in the Ukrainian capital of Kyiv.

The U.K. Foreign Office said it also had information that Russian intelligence services remained in contact with several former Ukrainian politicians, including an ex-prime minister.

"The information being released today shines a light on the extent of Russian activity designed to subvert Ukraine, and is an insight into Kremlin thinking," Foreign Secretary Liz Truss said in a statement.

"This is very much part of the Russian toolkit," U.S. Secretary of State Antony Blinken said on CNN's State of the Union on Sunday. "It runs the gamut from a large, conventional incursion or invasion of Ukraine to these kind of destabilizing activities in an attempt to topple the government, and it's important that people be on notice about that possibility."

Russia's Ministry of Foreign Affairs called the allegations "disinformation" and "nonsense" in a tweet on Saturday and said it was another example of Western nations escalating tensions around Ukraine.

Andrea Kendall-Taylor, a fellow at the Center for a New American Security and a former senior intelligence officer, told NPR's Weekend Edition on Sunday that it's fair to question the details of the U.K. report, but that interfering in Ukraine's government is consistent with what Russia appears to want to accomplish in the region.

"What Russia wants is to have some autonomy in the East that would give Russia a veto over Ukraine's foreign policy, and they're looking for a guarantee that Ukraine will not join NATO," Kendall-Taylor said. Doing so would likely require toppling the government of Ukrainian President Volodymyr Zelenskyy government, she said, "and/or securing a demanding military position that can help Russia extract those demands from Kyiv and the United States and NATO."

Last week the Treasury Department's Office of Foreign Assets Control sanctioned four Ukrainians, including two sitting members of parliament, for engaging in "Russian government-directed influence activities to destabilize Ukraine."

People are preparing for conflict but hoping for peace

NPR's Central Europe Correspondent Rob Schmitz reports that the mood in Kyiv is one of "patient resolve," with restaurants full and children sledding on snow-dusted hills. It's not that citizens are naive about the possibility of a military incursion, but rather that Ukrainians have said they've adjusted to life under the constant threat of Russian aggression.

"We have been living in a state of war for the last seven years going on eight now," Lesia Vasylenko, a Ukrainian member of parliament, told NPR.

"Physically, psychologically, emotionally, it would be impossible if all of us up to now would be still stressed, would be concerned 24/7 and showing signs of anxiety. You would see a different Ukraine then," she said.

Russia has said it has no plans to invade Ukraine, but the build-up of Russian troops along the border has prompted the U.S. to provide Ukraine with increased military aid for national defense.

A nearly 200,000-pound shipment of "lethal aid" approved by President Biden, including ammunition for Ukraine's front-line troops, arrived in the country over the weekend, the U.S. Embassy said.

Blinken said on CNN that the U.S. has given Russia "two paths" through the current crisis. "There's the path of diplomacy and dialogue," he said, "but there's also a path of its renewed aggression and massive consequences that we have been building now for many weeks."

Pope Francis has called for an international "day of prayer for peace" on Wednesday, urging politicians to find a nonviolent solution to the crisis and expressing concern over the security of Europe.

Meanwhile the head of the German navy has resigned after saying that Ukraine would not be able to regain the Crimean Peninsula, which Russia annexed in 2014, and suggesting that Russian President Vladimir Putin deserved "respect," according to the Associated Press.

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