(CNN) A desperate rescue attempt managed to save half of a pod of sperm whales which beached off the coast of Aceh, Indonesia.

WWF Indonesia said 10 whales were stranded on Monday, seven of whom were returned to the water thanks to the efforts of the navy and locals.

The LIVE stranding of 10 sperm whales in Aceh. Video credit WWF Indonesia @WWF_ID @WWF via Dwi Suprapti. pic.twitter.com/YgiW9pN3AD — Strandings Indonesia (@stranding_ID) November 13, 2017

Three whales died on the beach, and in a heartbreaking development for the rescuers, one of the animals that had been saved came back and was stranded again, this time fatally.

Dwi Aryo Tjiptohandono, WWF Indonesia's marine and fisheries campaign coordinator, said the group was investigating how the whales had come to be stranded. Autopsies will be carried out on the dead animals.

Rescuers attempt attempt to push stranded whales back into the ocean at Ujong Kareng beach.

He added the rescuers fear the six whales returned to the sea might attempt to come back for the four dead animals, risking being beached again.

Read More