But while conducting aerial surveys for the government this year, Elephants Without Borders said it had come across dozens of elephant carcasses, many with their tusks missing.

In a report in August, the charity’s director, Mike Chase, wrote that he had never seen so many dead elephants at once, though they had apparently died over a period of about three months. Mr. Chase attributed the deaths to a poaching surge, and the charity said in an email at the time that it had reached out to the government but had been ignored.

But the government immediately disputed both the group’s numbers and the assumption that all the dead elephants had been hunted for their ivory, calling the reports “false and misleading.” Survival International, which advocates for the rights of indigenous peoples, agreed.

In a visit to Chobe National Park last week, officials counted 19 dead elephants, only six of them killed by poachers, the government said. The rest had died of natural causes or in conflicts with villagers, the government said. Addressing reporters on the trip, Churchill Collyer, the deputy director of the wildlife department, said, “We haven’t recorded any mass killing.”

In a statement last week, Elephants Without Borders insisted that it was “completely apolitical in its work,” but said that it had felt “a moral and patriotic duty” to report the high number of elephant carcasses observed during its survey, which began on July 3 and will finish in October.

The statement did not mention the original claim of 87 carcasses or address the resulting criticism, noting that the group was unable to release any further information until completing its final survey report.