Russia has ​mustered about 70 percent of the military power it will likely need to launch an attack on neighboring Ukraine, an invasion that would result in thousands of civilian casualties and a massive refugee crisis in Europe, US officials said. 

​President Vladimir Putin, who has amassed more than 100,000 troops and heavy weaponry along Ukraine’s border and continues to add to the forces daily, could have the necessary firepower in place by mid-February to launch a full-scale invasion, the officials said. 

In the last two weeks, the number of Russian battalion tactical groups arrayed along the border has risen to 83 from 60 as of last Friday ​and another 14 are in transit. ​

Officials say while the size and scale of a possible attack are unclear, a number of indicators suggest a window of opportunity beginning mid-month.

The ground is expected to reach peak freeze around Feb. 15, allowing for heavy machinery to move without being bogged down in mud, conditions that would last until the end of March. ​​

An exercise involving Russia’s strategic nuclear forces typically held each fall was rescheduled for the middle of this month and will continue into March. ​​

While the ​officials did not suggest the use of nuclear weapons in an invasion, the exercises – most likely involving the test-launching of unarmed long-range missiles on Russia soil – could be staged to send a message to the West about intervening in any conflict. ​

A full-scale invasion would topple the government in Kyiv in a matter of days and result in mass casualties. ​

Ukraine could suffer 5,000 to 25,000 troop casualties, while Russia’s troop casualties could be between 3,000 and 10,000.

Civilian casualties could range from 25,000 to 50,000, according to ​US estimate​s, while millions of refugees would descend upon Europe as they fled the fighting. 

While P​resident Biden has said no US forces will be sent to Ukraine to fight, the first members of the 82nd Airborne Division landed in Poland on Saturday, part of the deployment of 3,000 ​troops to Poland and Romania to deter Russian aggression in Eastern Europe and show support for NATO members. 

While Poland and Romania are NATO members, Ukraine is not, but the former Soviet satellite has received millions of dollars in US military equipment over the past couple of years. ​

The deployment of US troops follows claims by the Defense Department that ​the US has intelligence that Moscow is intending to use a fabricated video showing Ukrainian forces attacking Russian troops as a pretext for an invasion.

​Pentagon press secretary John Kirby told reporters ​last Thursday ​that the video would be “very graphic propaganda” and include images of “corpses, and actors that would be depicting mourners, and images of destroyed locations, as well as military equipment, at the hands of Ukraine or the West.”​

But US officials reiterate that they don’t believe Putin has made a decision about whether to invade, and in the meantime, diplomatic efforts continue to resolve the standoff. ​​

French President Emmanuel Macron is scheduled to travel to Moscow on Monday to meet with Putin and then head to Kyiv on Tuesday. ​​

Germany Chancellor Olaf Scholz will go to Kyiv on Feb. 14 and Moscow the ​next day. 

With Post wires​​