The heavy loss of high-ranking Russian military officers has stunned Western security officials, who last confirmed an official tally of seven generals in late March, though Ukraine has since announced more.
In March, Western officials had cited low morale as a reason Russian generals would be so close to the front.
They also pointed to potential communications and logistics issues on the Russian side, which could lead senior officers to use unencrypted channels and expose themselves to Ukrainian forces.
But the report by the New York Times points to direct assistance from the United States and other Western intelligence services as a major factor in the Ukrainian success.
The daily said the United States had provided details on the Russian military's mobile headquarters, which frequently change location, and that Ukrainian forces used that information in tandem with their own to conduct attacks on senior Russian officers.
President Joe Biden's administration has kept the military intelligence it is providing to Ukraine under wraps out of concern it could compromise its sources as well as be taken as a sign by Russia of direct hostility.
Earlier in the conflict, the Pentagon was similarly cautious about noting that only "defensive" weapons and equipment were being provided to Ukraine.
But it has since announced shipments of offensive weapons like heavy artillery, helicopters and attack drones.
It has also talked of training Ukrainian troops, including in Germany, to use the weapons they are receiving.
And instead of saying, as it did in February, that it wants only to help Ukraine survive, Washington now says its goal in the war is to debilitate Russia for the long term.
"We want to see Russia weakened to the degree that it can't do the kinds of things that it has done in invading Ukraine," US Secretary of Defense Lloyd Austin said after a visit to Kyiv in late April.
The Pentagon did not immediately respond to request for comment on the Times report.