BANGKOK (DPA) - Aerial drone footage has revealed that a total of 11 elephants had died after plunging into a waterfall in Thailand, officials said on Tuesday (Oct 8), raising the earlier death toll of six.

Over the weekend, national park officials said six elephants fell into the Haew Narok Waterfall in Thailand's north-east and drowned, while two others survived the gushing waters after trying to save a calf that did not survive.

Nuttapong Sirichana, governor of Nakhon Nayok province, told reporters at a Tuesday press conference that officials discovered the bodies of five more elephants at the waterfall after analysing drone footage taken on Monday afternoon.

"This is an analysis from the drone footage," Nuttapong said. "We cannot walk in to inspect it ourselves yet because the water levels are high with strong currents."

He said officials were only able to spot the additional bodies of elephants after the sky had cleared up on Monday.

Park officials initially discovered a three-year-old elephant drowning in the waterfall after they heard loud elephant cries in the early hours of Saturday.

Two elephants had been watching the distressed infant before stepping into the water in an effort to help. The young elephant did not survive and officials later found five other drowned elephants on the first level of the large three-tiered waterfall, which has been temporarily closed to visitors.

Nuttapong said the two elephants were not part of the additional casualties.

Elephant experts have said that the animals tend to react instinctively and offer help when it sees another in danger.