As Russian troops retreat from northern Ukraine and focus operations on the country’s east and south, the Kremlin is struggling to scrape together enough combat-ready reinforcements to conduct a new phase of the war, according to American and other Western military and intelligence officials.
Moscow initially sent 75 percent of its main ground combat forces into the war in February, Pentagon officials said. But much of that army of more than 150,000 troops is now a spent force, after suffering logistics problems, flagging morale, and devastating casualties inflicted by stiffer-than-expected Ukrainian resistance, military, and intelligence officials say.
There are relatively few fresh Russian troops to fill the breach. Russia has withdrawn the forces — as many as 40,000 soldiers — it had arrayed around Kyiv and Chernihiv, two cities in the north, to rearm and resupply in Russia and neighboring Belarus before most likely repositioning them in eastern Ukraine in the next few weeks, U.S. officials say.
The Kremlin is also rushing to the east a mix of Russian mercenaries, Syrian fighters, new conscripts, and regular Russian army troops from Georgia and easternmost Russia.
Whether this weakened but still very lethal Russian force can overcome its blunders of the first six weeks of combat and accomplish a narrower set of war aims in a smaller swath of the country remains an open question, senior U.S. officials and analysts said.
“Russia still has forces available to outnumber Ukraine’s, and Russia is now concentrating its military power on fewer lines of attack, but this does not mean that Russia will succeed in the east,” Jake Sullivan, President Biden’s national security adviser, said on Monday.
“The next stage of this conflict may very well be protracted,” Mr. Sullivan said. He added that Russia would probably send “tens of thousands of soldiers to the front line in Ukraine’s east,” and continue to rain rockets, missiles and mortars on Kyiv, Odesa, Kharkiv, Lviv, and other cities.
U.S. officials have based their assessments on satellite imagery, electronic intercepts, Ukrainian battlefield reports, and other information, and those intelligence estimates have been backed up by independent analysts examining commercially available information.
Earlier U.S. intelligence assessments of the Russian government’s intent to attack Ukraine proved accurate, although some lawmakers said spy agencies overestimated the Russian military’s ability to advance quickly.
As the invasion faltered, U.S. and European officials have highlighted the Russian military’s errors and logistical problems, though they have cautioned that Moscow’s ability to regroup should not be underestimated.