In a statement, the government said the controlled hunting area where the animal was hunted was issued with an elephant-hunting quota and the license to hunt was obtained from the Department of Wildlife and National Parks.
The elephant in question had been put a collar around its neck to enable its tracking for research purposes.
The professional hunter, the statement said, claimed that the collar was not visible as the elephant was in a full-frontal position.
"Michael Lee Potter, a professional hunter and Sean Michael Sharp, a citizen hunting license holder claimed to have encountered several bull elephants in thick bushes north of Dobe Border Post," read the statement.
Although this was a legal hunt, the government said the killing of the collared elephant is regrettable and investigations by the Department of Wildlife and National Parks are at an advanced stage with a view to understanding exactly what transpired.
"We do not condone the shooting of collared animals and will take all the necessary measures to ensure that this does not occur again," the government said.
It added: “Killing of collared animals is not permitted under any circumstances and appropriate measures shall be taken against transgressors, including revocation of their licenses.”