“Russia is stealing Luhansk, Donetsk, Kherson, and Zaporizhzhia regions from Ukraine and threatening the world with nuclear weapons,” Estonian Prime Minister Kaja Kallas said in a statement on Friday. The taken territory is “comparable to Austria and Belgium combined,” she noted, or “30% of Germany.” Add in Crimea, which Russia invaded and annexed from Ukraine in 2014, and it’s the equivalent of about 40% of Germany, she noted.

The U.S. responded with sanctions on more than 1,000 individuals and companies—within and outside of Russia—deemed to be helping Moscow’s war effort. “Make no mistake: These actions have no legitimacy,” President Joe Biden said of the annexation.

Vadym Skibitsky, deputy intelligence chief in Ukraine, said this week that his nation’s military intelligence ranks the threat of Russia using tactical nuclear weapons as “very high.” Speaking to the Guardian, he noted such weapons are about 100 times more powerful than the type of missiles that Russia has used against Ukraine so far.

He said Putin’s forces would likely use the weapons to “target places along the frontlines with lots of [army] personnel and equipment, key command centers, and critical infrastructure,” adding, “Everything will depend on how the situation develops on the battlefield.” 

The situation has so far not developed well for Russia. A lightning counteroffensive by Ukraine earlier this month proved embarrassing for Moscow—one military expert called it a “rout”—leading to increased pressure on Putin from both anti-war protestors and nationalists critical of the battlefield strategies.

Military experts in the West have also questioned Russian strategies, with the Institute for the Study of War, a U.S. think tank, saying earlier this month they seemed “increasingly divorced from the overall realities of the theater.”

Nuclear weapons and ‘unpredictable ways’

Fears of a pressured Putin resorting to nuclear or chemical weapons have also increased outside of Ukraine amid Russia’s faltering invasion. Rose Gottemoeller, former deputy general of NATO, told BBC Radio’s Today this month she fears Russian forces “will strike back now in really unpredictable ways that may even involve weapons of mass destruction.” 

A nuclear hit could come as a “a single strike over the Black Sea or perhaps a strike at a Ukrainian military facility,” she said. “I do worry about that kind of scenario.” 

Last week, Ukrainian President Volodymyr Zelensky warned Putin would use the annexation as an excuse to say that Russian territory was being attacked by the West.

“He has to take steps to justify,” Zelensky said of Putin. “He says, ‘See, let’s look at it. I am not afraid of Ukraine. It was a special operation, but…now the West attacks our territories.”

Putin last week announced a partial mobilization of up to 300,000 military reservists to fight the war. The move sent hordes of Russian men fleeing the country, fearful the draft might expand to include them.

Yesterday, the U.K.’s defense ministry estimated the size of the exodus “likely exceeds the size of the total invasion force Russia fielded in February,” when the invasion of Ukraine began.