Alexei Nikolskyi/RIA Novosti/Kremlin/Reuters
The US has intercepted communications that show Russian officials expressing concern that Russian President Vladimir Putin doesn't realize how bloody and difficult a large-scale invasion of Ukraine could be, CNN reported, citing several people familiar with the intelligence.
"In the assessments we see it is clear some people on the [Russian] defense side are not really understanding what the game plan is," a senior European official told CNN, adding that some officials see it as "a very difficult game plan to stand up."
But the report also said there is no evidence that the officials are opposed to Putin's broader plans or would object to his orders.
In recent days, US officials have said that Russia has gathered 70% of the forces necessary to launch a full-scale invasion of Ukraine, though Chairman of the Joint Chiefs of Staff Gen. Mark Milley suggested late last month that Russia could probably do it with what it already has in place.
US intelligence and military assessments indicate that a large-scale Russian invasion of Ukraine could lead to up to 50,000 civilians casualties, see Kyiv fall in just two days, and result in up to five million refugees, according to reports from The New York Times and others.
Russia, which has gathered roughly 130,000 troops on Ukraine's border, has dismissed these bleak assessments.
"Madness and scaremongering continues...What if we would say that US could seize London in a week and cause 300K civilian deaths?" Russia's deputy ambassador to the United Nations, Dmitry Polyanskiy, said in a tweet on Sunday.
The Kremlin claims it has no plans to invade Ukraine, despite amassing a huge force on its border. Russia invaded Ukraine in 2014, annexing Crimea in the process. Since then, the Kremlin has also backed rebels in a war against Ukrainian forces in the eastern Donbass region.
Russia's aggressive posture toward Ukraine has seen tensions between Moscow and the West reach historic heights, but Putin has blamed the contentious dynamic on NATO, accusing it of disrespecting Russia's red lines in the region.
The Kremlin has made demands for a number of binding security guarantees from the West amid the Ukraine tensions. Among other things, Russia's demands include banning Ukraine and Georgia from ever joining NATO, which the alliance and the Biden administration have made clear is a non-starter.
President Joe Biden has warned Russia it will face severe economic consequences if it invades Ukraine, but Biden has ruled out sending US troops to defend Ukraine in the event of a Russian military incursion. Ukraine is not a NATO member, and the US is not obligated to defend it.
That said, the US and other NATO countries have supplied Ukraine with lethal aid, including Javelin anti-tank missiles.
Biden "has been clear for months now that the United States is not sending forces to start a war or fight a war with Russia in Ukraine," White House national security advisor Jake Sullivan told Fox News on Sunday, adding that "we have sent forces to Europe to defend NATO territory."
Biden has ordered the deployment of several thousand US troops to NATO member countries in the region to bolster NATO's eastern flank and as a show of support for the alliance.
In an appearance on NBC's "Meet the Press" on Sunday, Sullivan said "a military escalation and invasion of Ukraine could happen at any time." He added that the US believes "the Russians have put in place the capabilities to mount a significant military operation into Ukraine, and we have been working hard to prepare a response."
Although it is concerned, the US has also said that it remains unclear whether or not Putin has made a decision to invade Ukraine.