Russia is looking to address the shortage of troops in part by compelling soldiers wounded earlier in the war to return to combat, recruiting personnel from private security companies and even recruiting from prisons, according to a US official.
The official, who spoke to the Associated Press on the condition of anonymity, added that the intelligence community has determined that one step that Russia's Defence Ministry is expected to take soon is recruiting convicted criminals to enlist "in exchange for pardons and financial compensation".
Mr Putin's decree, which takes effect on January 1, did not specify whether the military would beef up its ranks by drafting a bigger number of conscripts, increasing the number of volunteer soldiers or using a combination of both.
But some Russian military analysts predicted it would rely heavily on volunteers, a cautious stand reflecting the Kremlin's concerns about possible fallout from an attempt to increase the draft.
The presidential decree aims to boost the overall number of Russian military personnel to 2,039,758, including 1,150,628 troops.
A previous order put the military's numbers at 1,902,758 and 1,013,628, respectively, at the start of 2018.
Colin Kahl, the US Defence Department undersecretary for policy, told reporters earlier in August that the US estimates Russia took heavy casualties in the first months of the war.
"There's a lot of fog in war, but I think it's safe to suggest that the Russians have probably taken 70 or 80,000 casualties in the less than six months," Mr Kahl said.
"Now, that is a combination of killed in action and wounded in action and that number might be a little lower, a little higher, but I think that's kind of in the ballpark."
The US has frequently downgraded and unveiled intelligence findings over the course of the grinding war to highlight plans for Russian misinformation operations or to throw attention on Moscow's difficulties in prosecuting its war against Ukraine, whose smaller military has put up a stiff resistance against the militarily superior Russian forces.
The Biden administration unveiled findings earlier this week that Russia has faced technical problems with Iranian-made drones acquired from Tehran this month for use in its war with Ukraine.
Russia picked up Mohajer-6 and Shahed-series unmanned aerial vehicles (UAVs) over several days this month as part of what the Biden administration says is likely part of a Russian plan to acquire hundreds of Iranian UAVs for use in Ukraine.
White House National Security Council spokesman John Kirby said on Wednesday that Russia has been having "some difficulties" and experiencing "the limits on some of the capabilities" of the Iranian drones since receiving them.