According to Bloomberg, citing its military sources, the U.S. has shared intelligence including maps with allies in Europe, that "shows a buildup of Russian troops and artillery to prepare for a rapid, large-scale push into Ukraine from multiple locations".
The head of Ukraine's defense intelligence also told Military Times on Saturday, that Russia is planning an attack around the end of January or early February, adding the invasion would likely involve "airstrikes, artillery and armor attacks", followed by airborne and amphibious assaults, as well as smaller land incursions through its neighboring Belarus.
The Kremlin in response, have gone a verbal offensive, while stressing the importance of a still unconfirmed U.S.-Russia summit, which Moscow says is in the works.
It added that the West was "artificially" raising tensions by claiming Russia is planning an invasion.
The latest reports come as tensions have been on a continuous rise, after Russia annexed the Crimea peninsula in 2014.
Both the U.S. and its allies have been critical of the annexation, with President Joe Biden in February, reiterating that the U.S. "does not and will never recognize Russia's purported annexation of the peninsula".