Photo shows one of the nine stray elephants that were electrocuted after knocking down a power line in Botswana on Sept. 19. (Xinhua)

GABORONE, Sept. 21 (Xinhua) -- At least nine stray elephants have been electrocuted after knocking down a power line in Botswana, the country's environment minister has confirmed.

In a telephone interview, Minister of Environment, Natural Resources Conservation and Tourism Tshekedi Khama said Wednesday the incident occurred on Tuesday night and investigations are ongoing.

Khama said the herd is believed to have strayed from the northwestern Makgadikgadi Pans Game Reserve and into a nearby village of Dukwi while in search for water.

"Preliminary investigations into the incident suggest that the freak accident happened after one (elephant) knocked over an electricity pole and a power line fell on them," said Khama.

He said the accident is the first of its kind in Botswana.

According to Khama, all the 18 elephant tusks were recovered, as authorities were informed of the incident well before the poachers could have pounced on them.

Botswana has the largest elephant population in Africa at over 135,000, according to a 2015 aerial census.

The International Union for Conservation of Nature (IUCN) has said the number of African elephants has fallen by around 111,000 to 415,000 in the past decade, the worst drop in 25 years.