Washington - Russian President Vladimir Putin's order to put Russian nuclear forces on high alert during his invasion of Ukraine is an escalation that could make things "much, much more dangerous," a senior U.S. defence official said on Sunday.
Putin gave the order as Washington assesses that Russian forces are suffering unexpected battlefield setbacks in their four-day-old invasion due to stiff Ukrainian resistance and planning failures that have left some units without fuel or other supplies, U.S. officials said.
The Pentagon learned of the heightened Russian alert from Putin's televised announcement, the senior U.S. defense official said, instead of from American intelligence sources.
Just after Putin spoke, Defense Secretary Lloyd Austin, General Mark Milley, chairman of the Joint Chiefs of Staff, and the top U.S. commander for Europe, General Tod Wolters, held a pre-scheduled meeting at 8:30 a.m. (1330 GMT) at which they discussed the Russian president's decision.
Although Washington was still gathering information, Putin's move was troubling, the official said, speaking on condition of anonymity.
"It's clearly, essentially, putting in play forces that, if there's a miscalculation, could make things much, much more dangerous," the official said.
Asked whether the United States would continue to provide military assistance to Ukraine following Putin's announcement, the official said: "That support is going to go forward."
As missiles rained down on Ukrainian cities, thousands of civilians, mainly women and children, were fleeing the Russian assault into neighboring countries.
The capital Kyiv was still in Ukrainian government hands, with President Volodymyr Zelenskiy rallying his people.
The United States assesses that Russia has fired more than 350 missiles at Ukrainian targets so far, some hitting civilian infrastructure. But the U.S. official expressed deep concern about what the Pentagon believes are indications that Russian forces -- which have broadly appeared to focus on military targets -- might be shifting strategy.
Citing a Russian offensive on the Ukrainian city of Chernihiv, north of Kyiv, the official cited early signs that Russia was adopting siege tactics.
"It appears that they are adopting a siege mentality, which any student of military tactics and strategy will tell you, when you adopt siege tactics, it increases the likelihood of collateral damage," the official said.
Reuters