Aerial photo shows a carcasse in the Okavango Delta after a cluster of 'mass die-offs'. A total of 275 elephants have died since March in Botswana, which is home to a variety of wildlife including elephants, in what is being described as a conservation disaster. (Photo: IC)

Botswana reported more dead elephants and authorities are investigating the cause of death of hundreds of elephants in Seronga and Eretsha villages in the North-West of the country.

Wave Kashweeka, a principal veterinary officer at the Department of Wildlife and National Parks, told reporters at Seronga on Thursday that they had now verified 281 elephant carcasses.

"From the end of April up to date, we have been doing our investigations as to why these elephants are dying. Most carcasses were reported around this village and surrounding villages but following a two-day area survey, we noticed that there were carcasses also on the northern side near the Namibian border," said Kashweeka.

"We have removed and collected 122 tusks from 62 animals and from the 62 carcasses two were found with one tusk," said Kashweeka.

For his part, Cyril Taolo, acting director of the wildlife and National Parks ruled out anthrax and poaching because the carcasses were found with their ivory.

"We have been in contact with our neighbours, Namibia, Angola, Zambia and Zimbabwe as we were keen to understand if they were seeing the similar mortalities," said Taolo.

The department of wildlife is expecting to receive the test result sample this week. Botswana's elephant population is estimated at around 130,000.