Zelensky questions U.S. warnings of "imminent" invasion in Biden call

• The Ukrainian government, which is worried about the effects of such statements on the economy and public morale, has been contending that the threat of an invasion is real but not any higher than in previous months.

Behind the scenes: When Zelensky raised the White House warnings of an “imminent” threat, Biden pointed to the possibility that Russia will invade once the ground freezes, and he said that’s why the U.S. is sending so much weaponry.

• The three sources disagreed on the exact language Biden used. The White House has denied a CNN report that Biden said an invasion was “virtually certain,” but said he reiterated the distinct possibility Russia would invade in February.

State of play: While the White House is continuing to seek a diplomatic off-ramp, the Kremlin signaled Thursday that the security proposals formally presented yesterday by the U.S. and NATO don't address Russia's "fundamental" concerns.

• Moscow has said that if its demands aren't met, it will opt for a "military-technical" solution, but denies any intention to invade Ukraine.
• While there's a growing consensus among close watchers of Russia's military that some sort of escalation is likely soon, the debate continues as to whether Russia would opt for smaller operations to destabilize Ukraine or a full-scale invasion toward the capital, Kyiv.

Russia's rapid movement into Belarus — which NATO Secretary-General Jens Stoltenberg said Wednesday was taking place "under the disguise of an exercise" — has convinced some analysts that Putin is planning a major invasion.

• Konrad Muzyka, a defense analyst focusing on Russia and Belarus, tweeted Thursday that, with 10 army groups now positioned at various points near Ukraine's borders, this would have to be the largest exercise in Russia's modern history.
• And while some analysts contend Russia has only assembled enough troops for a limited incursion, Rob Lee, a former U.S. Marine officer and an authority on Russia's military capabilities, believes Russia now has the necessary equipment in place for a full-scale invasion and could fairly quickly send the troops to man it.

What's next: Michael Kofman, an expert on Russia's military at CNA, told Axios the movements of Russian troops and equipment suggest preparations for a large-scale military operation.

• He estimates that it could take about three to four weeks to have the various pieces in place, based on current deployments, though Moscow could opt for a "rolling start" to its operations before then, including potential cyberattacks or missile strikes.

If Putin does invade, Kofman expects Russian artillery and air power to degrade Ukrainian defenses, which have improved since 2014 but are still not a match for Russia's capabilities. The fighting in the early days would be "quite intense," he says.

• By the time the tanks started moving, Ukrainian forces near the borders would face a hard choice: "Be encircled or consider organized retreat," he says.

Kofman doesn't expect Russia to "commit to urban warfare," however. Instead, he believes the likely objective would be to occupy a significant amount of territory, or encircle Kyiv, and force a capitulation from the government. He believes the Russian military would expect to be able to accomplish that task fairly quickly.

• One key question is whether Russia would limit its operations to eastern Ukraine or attack in the west as well, Kofman says.
• He notes that the Russian military has extensive experience with counterinsurgency campaigns, including in Chechnya, and may be willing to risk a lasting occupation until it gets a friendly government or an enforceable security pact from Kyiv.