World Athletics has been reimbursed for more than three years' worth of costs incurred since the suspension of the Russian Athletics Federation (RusAF) in November 2015.
Financial statements obtained by The Sports Examiner say that the governing body received "an amount of $3.2 million (£2.5 million/€2.8 million)" from RusAF on May 31, 2019.
The payment was said to be "as reimbursement of costs incurred by [World Athletics] since the suspension of RusAF in 2015".
The reimbursement was said to include "expenses incurred by [World Athletics] till March 31, 2019".
The revelation comes as a July 1 deadline for payment of half of a $10 million (£7.9 million/€8.7 million) fine imposed on RusAF last March is looming.
The fine was imposed as part of a package of measures recommended by the World Athletics Task Force and approved by the World Athletics Council.
World Athletics also reinstated the Authorised Neutral Athlete (ANA) process with a cap at 10 athletes.
Should the payment not be made the ANA process will be suspended.
The sport's gradual emergence from coronavirus lockdown got under way in earnest last week in Oslo, when local hero Karsten Warholm set a world best for the infrequently-contested 300 metres hurdles while running alone in a largely empty stadium.
The next big event is due to be the Inspiration Games on July 9 based in Zurich.
This is set to involve 30 athletes competing in eight disciplines across seven stadia.
The Herculis event in Monaco, meanwhile, has been re-scheduled for August 14.
Regarding the RusAF situation, World Athletics said last week: "There were serious allegations last year that previous RusAF administration breached the anti-doping rules and the World Athletics Council was severely let down.
"That led World Athletics to approve a new set of criteria for reinstatement of [RusAF].
"A fine, and the payment terms, were one of those criteria.
"We have, as we agreed to do, set-up a process to facilitate the granting of ANA status for athletes returning to competition and stand ready to implement this as soon as the fine has been paid.
"The deadline for the payment is July 1, 2020."
The Sports Examiner claims to have been sent the entire 300-page-plus document file from World Athletics' 52nd Congress, held in Qatar last September.
As previously reported, World Athletics sustained an overall deficit of some $39 million (£30.8 million/€34.3 million) over the two years 2017 and 2018.