Musoke told AFP that the elephants were killed on March 25 in the park, which is near military barracks in western Uganda, and an acid was used to extract their tusks.

"This was the most gruesome massacre of elephants we have ever seen", she said, adding that the bullets must have been fired from modern guns, "not those from the local poachers."

"The acid helped them to pull the tusks right from the skulls instead of cutting them half way using cutters," Musoke explained.

"Three were male and another three were female while the seventh was a calf," she added.

Musoke said the country's entry and exit points have been notified to look out for fresh tusks and that security at Queen Elizabeth National Park would stepped to avoid similar incidents.

Last November's decision by the 12th Convention on International Trade in Endangered Species (CITES) to lift a ban on ivory trade for Botswana, Namibia and South Africa, has been largely blamed for increasing poaching of elephants.

"Poaching of elephants had been wiped out when an ivory trade ban was in place... but there seems to have developed a new market now, which has attracted poaching," Musoke said.

Queen Elizabeth National Park is home for about 1,000 elephants, almost half the number of those found in the east African nation.

SPACE.WIRE