WASHINGTON (BLOOMBERG) - President Vladimir Putin can be expected to brandish threats to use nuclear weapons against the West if stiff Ukrainian resistance to Russia's invasion continues, draining conventional manpower and equipment, according to a new assessment by the Pentagon's Defence Intelligence Agency. "As this war and its consequences slowly weaken Russian conventional strength, Russia likely will increasingly rely on its nuclear deterrent to signal the West and project strength to its internal and external audiences," he added. Mr Putin already has announced that he has put Russia's nuclear arsenal on a state of higher alert. 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 at Tuesday (March 15). A senior Pentagon official told reporters on Thursday that the invasion is largely stalled, with Russia relying so far on more than 1,000 long-range missile strikes into Ukraine.