在她自5月以來首次公開評論美國的戰爭情報時，海因斯女士表示，俄羅斯的入侵將 "在很長一段時間內 "持續下去，"情況仍然相當嚴峻"。
這可能意味着莫斯科更加依賴 "不對稱工具 "來打擊敵人；包括網絡攻擊，努力控制能源資源，甚至核武器。
Moscow's troops have been so weakened by combat, however, that US officials assess they are only capable of making slow territorial gains.
Mr Putin still has the same goals as the ones he held at the start of the conflict, the US's top intelligence officer Ms Haines said - to take most of Ukraine.
"We perceive a disconnect between Putin's near-term military objectives in this area and his military's capacity, a kind of mismatch between his ambitions and what the military is able to accomplish," she told a US Commerce Department conference.
In her first public comments of US intelligence on the war since May, Ms Haines' suggested Russia's invasion will grind on "for an extended period of time" and that "the picture remains pretty grim".
The most likely scenario would see Russian forces remaining preoccupied with the conflict for a long time, she said, limiting Moscow's wider military capabilities.
"Russian troops are unlikely to be able to conduct multiple simultaneous operations" for as long as the war grinds on, Ms Haines said, based on US intelligence assessments.
It may mean Moscow becomes more dependent on "asymmetric tools" to target its enemies; including cyber attacks, efforts to control energy resources and even nuclear weapons.
Ms Haines' comments came on Wednesday after Nato leaders pledged to stand behind Ukraine for as long as it takes - boosting their troop presence across Europe and inviting Finland and Sweden to join the group.
"If Nato troops and infrastructure are deployed, [Russia] will be compelled to respond," Mr Putin said while on a trip to Turkmenistan.
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