Russian President Vladimir Putin is likely to brandish threats to use nuclear weapons against the West if stiff Ukrainian resistance to Russia’s invasion continues, draining conventional manpower and equipment, Pentagon’s Defence Intelligence Agency said.

In its new 67-page summary of worldwide threats, Lieutenant General Scott Berrier, director of the Defence Intelligence Agency said, “Protracted occupation of parts of Ukrainian territory threatens to sap Russian military manpower and reduce their modernised weapons arsenal, while consequent economic sanctions will probably throw Russia into prolonged economic depression and diplomatic isolation.”

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The combination of Ukraine’s defiance and economic sanctions will threaten Russia’s “ability to produce modern precision-guided munitions,” Berrier said in testimony submitted to the House Armed Services Committee for a hearing on Thursday.

“As this war and its consequences slowly weaken Russian conventional strength,” Berrier added, “Russia likely will increasingly rely on its nuclear deterrent to signal the West and project strength to its internal and external audiences.”

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The agency’s grim appraisal of the war’s broader stakes comes on the eve of a call between President Joe Biden and China’s President Xi Jinping. Even as US officials struggle to discern China’s position on the war, Biden will seek Xi’s help ratcheting up pressure on Moscow to end it.

Meanwhile, Putin has already announced that he’s put Russia’s nuclear arsenal on a state of higher alert. The Russian Embassy in Washington didn’t immediately return a request for comment on the Defence Intelligence Agency report.

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Unlike a report on global threats issued by multiple intelligence agencies last week with findings that predated the Russian invasion, the new report reflects information as of Tuesday.

A key motivation for the invasion, he said, is Russia’s determination “to restore a sphere of influence over Ukraine and the other states of the former Soviet Union.”

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He added that “despite greater than anticipated resistance from Ukraine and relatively high losses in the initial phases of the conflict, Moscow appears determined to press forward by using more lethal capabilities until the Ukrainian government is willing to come to terms favourable to Moscow.”